How long does it take for wisdom teeth to fully erupt?

Varies. Some wisdom teeth never fully erupt. If a person has room for wisdom teeth to erupt in their mouth then eruption occurs around ages 17 to 21.
Sometimes never. If you are 37 y/o & they are not erupted now, they never will. If you go to the dentist your situation can be evaluated & personal advice can be recommended. As a side note if they are not in by age 20 they can be evaluated with an xray if they ever will erupt. Unerupted or impacted wisdom teeth removed before age 25 is best for best repair to the extraction site.