髪があるかないかで何歳に見えるかが違ってくるって英語でなんて言うの？

• "Whether someone has hair or not can change how old they look."
  "whether ~ or not " 「〜があるかないか」
  "whether someone has hair or not" 「髪があるかないかで」
  "can change ~" 「〜が違ってくる」
  "how old they look" 「何歳に見える」

"髪があるかないかで何歳に見えるかが違ってくる"
- Depending on if you have hair or not, it will change how old a person looks.

• How old a person looks can drastically change depending on how much hair they have.

同じ60歳でも髪の毛がふさふさなのと、あまりないのでは、何歳に見えるかに差がある。
- Even between two 60 year old people, if one has a head full of fluffy hair and the other one doesn't have much, there's a difference in how old they look.