J.C.
I say do it. Why not? If they accept her into the program, then they think she can handle it. It's only pre-school - not first grade. Also, putting her in early does not mean that she is going to kindergarden early (although, if she is doing really well, they may give you that option).
I think that there is nothing wrong with putting a child into a learning environment early. If it's too much, you can pull her out and put her back into day care.
My daughter is a little over two and she is starting pre school in a few weeks (a 2 YO program). Good luck and don't stress - you can always pull her out if it's not working.