S.C.
I stand in your shoes almost to a T. I was 125 before I had kids. Like you, I'm short and that was a good weight for me (even though it's considered overweight for my height.) I got pregnant with #1 and gained over 50 lbs. 30 came off, but I still had that extra 20. Then I got pregnant with #2. Thankfully, I lost all that pregnancy weight, but am still stuck with the extra 20 lbs. I tried on a really nice dress and about puked when I saw myself in it. My arms were flabby and jiggly, my stomach looked like I was 6 months pregnant and I can't even talk about my butt and thighs. DISGUSTING. That was my motivation. I got Jillian Michaels 30 Day Shred from Netflix and have been doing it fairly religiously for over a month. I don't do it everyday, sometimes life gets in the way, but I do it at least 4 times a week. I noticed a difference in a few days. I felt better and had more energy. I don't own a scale, so I have no idea how much I weigh. I didn't measure before I started, so I don't know how many inches I lost. I do know that I can fit into my little black dress now :) I'm not "shredded" like she promises, but I can tell I look better. For the first time in a long time, my breasts are bigger than my stomach. ;)
I found that once I started working out, I started eating healthier too. I eat my fruit first at lunch so I'm not as hungry for the junky stuff. I don't go for second helpings at dinner. My portions are smaller as well. I'm a junk food junky and it's SO hard for me to watch my husband (who has a ridiculously high metabolism) eat Oreos one after another. I do allow myself to indulge in a treat, but instead of eating 10 oreos, I eat 2. For a midafternoon snack, I eat a handful of nuts. They fill me up far more than junk food. I can eat a small handful and feel satisfied.
The bottom line is that no one can motivate you but you. If you just get started, I think you'll find that motivation. YOU CAN DO IT!!! :D