It sounds like what she is doing now is not too much right now.
My daughter did 45 min 2x a week at 3 y/o
1 hr 2x a week at nearly 4 y/o
1.5 hrs 2x a week at late 4 early 5
1.5 hrs 3x a week at 5 y/o
then switched gyms at 6 y/o and went to 4 hrs 3x a week for a few months which then was downgraded to 3hrs 3x a week now, at 6 1/2 y/o (they shortened the class, she didn't change classes).
She's a very active child, also involved in taekwondo and diving 2x a week, and school and homework every day, and loves just about every sport out there. If it were up to her, she'd be in soccer, tennis, girl scouts and piano too, but I just can't do it all. I think you need to just watch your own child to see how they handle things. My kids hate being home bored. The more we do the better. Other kids like to have downtime, and get overwhelmed easier.
We didn't do privates at 3 y/o, was too young to spend that kind of money, but we did have her in a group class 2x a week and did open gym when we could. At her old gym, when she was 5 y/o, we did 1 hour a month with the head coach. They were very worthwhile lessons, and helped her to get a little one on one time with some harder skills (FHC, BHS, etc.) Now that she starting to compete, I wish we could do privates again, but we have yet to find a coach we like well enough, that has the time to do them, so she's just in her regular class.
Good luck with your daughter, sounds like she's doing great!