Eileen, 3y 2mo

Hello, eileenpiano!
I read all of your numbers. It seems like your child is in eye-hand development stage, when it takes to look for a correct key and corresponding note.
Keep up your good job!
You may consider to upload your video on You Tube and place the link here. This way I will be able to see what else is going on.

Dear Eileenpiano, thank you very much for sharing your videos! Picture worth 1000 words indeed
I can clearly see now that your child is on building eye-hand coordination advance stage. Why advance? Because she is now also have enough 'room' in her mind to develop fingers' awareness and starting managing her fingers.
It is obvious to me that right and left hemispheres of your child's brain are in excellent balance: her empiric and logic conduct go hand in hand together. She stops, because she wants to use the right fingers. It is so fun to watch!
Watch, please, the numbers on the right (timer). When it is going to be equal or less then amount of music notes played, it will be time to start working with both hands.
Playing with both hands is going to increase your child's min dramatically.
Keep us posted about your progress!

eileenpiano wrote: Is that a good stage to be at for her age?

It is perfectly normal. Before any child can walk, she has to have gravity/feet awareness. The same with the fingers and piano keys. Did you have a chance to read my book 'You CAN be a musician'?

In terms of playing with both hands, when the timer does reach that and it is time to start what is the best way to go about it?

We programmed the software the way that timer is catching any delay in pressing the piano keys. The best way is to see the child being comfortable and time is as close to 0 as possible. Child's comfort is priority, though. Our goal is not the perfect performance, but your child and her confidence and self-esteem.

Should I teach her the left hand separately then get her to put them together once the timer is good with left only?

Ask her. She will tell you, if she is ready.

Or is it better to try to add the left hand in to what she is already doing and play both together?

The key word is the willingness of your child. We can't open the flower petals before they are ready to bloom. Your child is perfect by nature. Let her develop organically. Let me know how it goes!