Hi
I'll play devils advocate...Your going to want to be careful... This is the age when childrens imaginations really start to develope. If she gets frightened her imagination may run away with her. She isn't old enough to understand time, so saying you'll be back in a few hours may as well be a week.
Night Terrors are very common at this age as well as nightmares. There are lots of things that scare toddlers but the biggest I think is being lost or left.
Now I'm not saying she won't benifit from some alone time but this may be a bit much for her to start with. Have you ever left her with a sitter? Did she do ok with that?
Toddlers are learning things so fast and as their exploring this world, they need to know they are safe and secure.
Now, children go into daycare all the time and some pick up bad habits not to mention colds. Some do really well and others hate it, so please take everything into consideration before taking this step.
As her mother you know what's best for her. If you think this is what she needs, then be be content with your decision :)
Good Luck
God Bless
K. SAHM of 3