Hi N.,
I went through the same struggle with my two children (twins). There are pluses and minuses to your question. I think if you have someone who can watch them that you trust and love then I would keep Cassidy there until she is a bit older. My two (girl and boy) are almost 2 1/2 years old and not been to any type of daycare or mother's day out. They are really wanting to play with other children. I am going to get them in soon - either this fall or spring. I have watched them learn and grow in the past year and am glad I have waited. While they pick up good habits, they can also pick up bad habits. Daycare is not a bad option at all, and something that is a godsend to most people who have to use it. I would personally not take Cassidy to daycare until you need to or when she is 2 years old and older. I just really think God intended us to raise them as long as we can with family and when we need to do something different we do. If I weren't blessed with free childcare (my mom) I would be using daycare or mother's day out. Basically, if you are not sure and going back and forth on it - trust your gut - and wait a bit. Your daughter is still at the age of learning things that she needs to learn from her grandmother and you. The rest, ABC's and socializing, will come later no matter what. I think using the first two years to really get them mentally and emotionally healthy is the best way to go.
On another note, your daughter might absolutely love it! If you have a neat place that you trust and know she will be well taken care of - go for it. You'll know if she doesn't like it by her demeanor and new actions once she is going and you can always change your mind!
Pray about it and trust your gut. God gave us really good "mommy" instincts...if we are quiet enough to listen. :) You seem like a neat mom!
S.