It's better to think in terms of distance thn to think in terms of focal length. The thing that controls the perspective distortion is distance from the subject. You should first decide what perspective you want, then choose the lens you need. Doing the opposite is allowing your equipment to control you.
If you don't have a long enough lens you can always crop reasonably. Just be careful about focus. Also, you can use a zoom lens and just don't admit it if you think it will damage your internet cred.