Unless you are entering her in a school program that uses Optimists, skip the Optimist.
The Optimist is a training boat for kids who want to race, other kids leanring in Optimists, tend to drop out of sailing.
Get a boat big enough for your daughter AND HER BEST FRIEND (or you for that matter). Young girls want to hang with their friends, a two person boat enables them to sail and to socialize. (Young boys want to follow the girls...)
An N10 is a nice learning boat N10 Association | Serving Sailors for N10 class boats
and used to be the predominate training boat in the NE. Wood versions are cheapo.
If you can use a dingy for cruising, buy something like a tech IC dingy Sailing and the Tech Dinghy
. She can sail it and then you take in on vacation and use it for frostbiting...