You're good at drinking juice out of a (plastic) bottle now, aren't you!
Now you can drink out of a bottle, just like mummy!
You want to drink out of a bottle like mummy, don't you?
「ペットボトルでジュース飲むのうまくなったね」= You're good at drinking juice out of a (plastic) bottle now, aren't you! / Now you can drink out of a bottle, just like mummy!
「ママと同じもの(ペットボトル)で飲みたいんだね」= You want to drink out of a bottle like mummy, don't you?
「あっ、少しこぼれちゃったね。」= Oops! You've just spilt a bit!
ボキャブラリー
good at ~ = ~が上手、うまくなった
plastic bottle = ペットボトル
drink = 飲む
just like mummy = ママと同じように
want to drink = 飲みたい
oops = あら!しまった!
spill (過去形・過去分詞):spilt/spilled = こぼす
a bit = ちょっと