Welcome and I already have a question for you. My 3 1/2 year old girl wakes between 4 and 5 am. She rarely will fall back asleep. I don't think this is actually a bedtime type issue. I have tried to work those out. She falls asleep between 6 and 6:30pm. Sometime when she wakes up she says she is "so tired" but she usually gets up. Do you have any thoughts or suggestions? BTW, I am a really lite sleeper and so is my mom. There are some quiet morning changes that start happening after 4 am.
Sleeping for 10 hours straight is pretty good for a 3 yr old.
You could try putting her down for an afternoon nap later and then try to keep her up at night until 7:30 or 8:00. She is just not on your schedule, but she sounds fine. Not much to do since this is not really a sleep problem, as you say.
There are things that kids can take to help them sleep, but I think she is fine.