When I think about it now, that was asking too much of a three-year-old.
Looking back, I think I made him/her do too much.
Now I think about it, those activities were too much for just a three-year-old child.
「今思えば、あの時は3才児に対してやらせすぎだったよね」＝ When I think about it now, that was asking too much of a three-year-old. / Looking back, I think I made him/her do too much. / Now I think about it, those activities were too much for just a three-year-old child.
ボキャブラリー
When I think about it now/Now I think about it＝ 今思えば
ask too much of ～ ＝ やらせすぎ、頼みすぎ、無理させる
three-year-old ＝ 3歳児
looking back ＝ 今考えると、過去を振りかえってみると
activities ＝ 習い事
too much ＝ 多すぎる、大変すぎり
イギリス 
