At what age did your child started LM?

Hi everyone!

My name is Rosie and I am very new to this forum. I just found out about early child education, and I was wondering if anyone here has started LM with their child at age two. How long did it took your child to subitizing? I introduced my 2years old to LM today and she completed the 6 quantity lesson for day 1, she finish it in less than 2mins or so it seem. Am I suppose to change the setting to make it longer? She already knows how to count to 20 and can recognize numbers, would this hinder her learning quantity-since I heard that they should learn quantities first.