She is definitely not too young. She is even within the traditional potty training window of 18 mo -2.5 yr. Training now will mean skipping the struggle of training later in her 2's.
Unfortunately I'm not chock full of resources for beginning potty training at this age. I've done elimination communication with my last few children and so potty training at 19 months was just a continuation of what we've already been doing.
But you could try
to be there when she wakes up from a nap or in the morning- if she is dry then, it's a great time to try to go. My daughter (21 months) likes to "read" books, brush her teeth, and play with certain toys (that she picks out before hand,) when she sits on the potty.
having a few things she likes to play with in the bathroom, so she can see them when she walks in to sit down.
having a cup of water in the bathroom for her to drink. Swallowing stimulates peristalsis in the bowels and being well hydrated will help with toileting as well. Chewing also stimulates peristalsis, so be prepared for her to need to poop around mealtimes...
If you let her go diaperless for a couple of days you should be able to figure out when she needs to go the most. And you may already have a good idea of when she poops every day- most children are fairly consistent.
You might want to consider buying a couple more potties and some cloth training pants. You will probably have to special order the pants off the internet, it's hard to find them sized for 18 mo-24 mo in the store. Then she can go diaperless or wear the training pants at home, with a shirt or dress, so she can learn to take herself. You can find waterproof cloth training pants that you can use in the car or when visiting, as well as the traditional cloth kind. I think cloth is better because she can feel the wetness better, and it's more like real underwear. The secondary potties go in rooms you are both in the most- probably your living room and kitchen, but YMMV. It is helpful to have an older child or yourself demonstrate using the potty in these rooms. As she is first re-learning to listen to her body's signals, she will not have very much time between knowing she needs to pee and cutting loose, so having a potty right there is helpful. Once she is going in the potty consistently, she will learn to tune in earlier and be able to wait longer, and you can phase out the secondary toilet spots.
When you go somewhere, take a small potty (we used a baby bjorn little potty, now she is sitting on the big seats) or an insert seat with you. Giant size ziplocs and a big diaper bag are helpful for discreet and hygeinic transport. Offer her the chance to potty before you leave- you probably already have a routine for this with your older child, just include the baby in it. Then as soon as you get where you are going, offer a chance to go again.
"Toilet learning" by Allison Mack is a good book to read together at that age, or there are a lot of more modern children's books and videos in the potty training world.
The most important thing is your attitude. This is something you are thinking about doing because you are listening to your child and following her lead, so you're starting from a healthy place. If during the process you find yourself getting irritated or angry, that's the time to stop, apologize if needed, and after the mess (if any) is cleaned up, put a diaper on for awhile. Consistency is important, but a postive attitude even moreso. A positive attitude, and one that is matter-of-fact- of course you want to learn to potty, just like you wanted to learn to walk and talk, of course you will learn from me and sister and daddy, when you are ready- and patience with the inevitable mistakes along the way- all this goes a long way. You probably didn't praise and reward M&M's for every step she took in the process of learning to walk- it isn't needed for toilet learning either. Just a positive attitude, ready to share her accomplishments with others (guess what baby did today!?) but not praising overmuch or rewarding. She will get the hang of it and be happy to be one of the big kids who uses a potty.
I checked out the Toilet Training in Less Than a Day book for my oldest, and let my husband try it out with him one day, because I couldn't bring myself to try it. His mother had used it with him with great success, so he was into it. My son made progress in the weeks that followed and learned within a few months of the episode, but he wasn't trained in one day. It is a method developed for teaching older children and adults who are mentally and physically disabled but have bladder and bowel awareness to use the toilet. There are some aspects of the book that I think are good- the doll that wets was very encouraging to my son- but overall my feeling was that I would be training an animal, not helping a little person who naturally wants to become independent and imitate her parents. Rewards aren't needed if your subject isn't reluctant, and a non-verbal 19 month old is a lot smarter than a dog. Just my opinion!
My daughter (21 mo) will usually come and find me if she makes a mistake. Often she will help clean up a pee puddle with a rag if she makes one. She will sometimes bring me her little potty if she goes, to let me know it is full- kind of nerve racking for her to carry it across the floor, but so cute! We just went on a weekend trip to my sisters. She is now peeing in public toilets (a little scary to use them when they are so small!) instead of just sitting or going in and refusing to sit. She continued to do all her poops in the potty at my sisters, just like she's been doing at home. We kept a diaper cover on top of her training pants as backup (there is a lot of carpet where we were staying) and she only peed in the toilet a couple of times, usually right after she woke up or when she had to poop. So we still have a long way to go with bladder consistency. At home we are between 60-75% of pee in the potty. But believe me, even just having her out of poopy diapers is such a relief! I definitely think it was worth cleaning up a few poopy messes on floors and chairs- and out of training pants- to not have to wipe it out of all her cracks and crevices and have her sitting in it on a daily basis in her diaper, KWIM? And she is taking herself to the bathroom with a toy or book, pulling down her pants if she is wearing them (often she just strips off entirely!) sitting, and then calling for me across the house to come and wipe her. Adorable and so much nicer than me having to track down that smell and remove it from my child's privates.
Take what you like and leave the rest- good luck on your journey!