One thing to add in here: your band director (or future band directors) may ask that you play with the whole section having "bells up... not buried in the stand". That way you can play at a lower dynamic but hold control and still give the audience a "bright sound". If you have a severe overbite or happen to need but are allergic to bifocals you will either have to memorize your music (and get a crick in your neck) or do something else.

The "something else" is perhaps to experiment with the bent-shank mouthpiece. I'm one of the "bifocal" guys but I am not allergic to them (in fact, bifocals are sooo much easier to read music and keep the bell up than with the multi-focal glasses!)

Not a problem if you play "off the side" since you can just angle your stand/stance so that the bell is still pointed in the right direction.