I think she's a little stressed about not being able to skip rope as well as her friends.
この場合、次のような言い方ができますよ。
ーI think she's a little stressed about not being able to skip rope as well as her friends.
「彼女は、友達と同じように縄跳びができないことがちょっとストレスのようです」
She's a little stressed about not being able to XX as well as her friends. で「彼女は友達同じようにXXできないのがすこしストレスに感じている」と言えます。
ご参考まで!