What if you have a tooth that has started growing at the age of 17 is it possible for it to grow further?

Yes Maybe: If you have an unerupted tooth it naturally, as part of the way the body works, erupts, breaking through the gum to its correct normal place in the dental arcade. Crowded teeth or extra teeth (supernumerary) can be prevented from erupting normally and become awkward and displaced. You need to see a dentist about this and take the professional advice.

YES IF WISDOM TOOTH: Your upper or lower third molars[wisdom teeth can still erupt fully or partially even up to the age of 21.If pain persists or an x-ray shows no room for full eruption or the tooth is pressing against the tooth in front of it than you may want to have it extracted so as to avoid future problems.