I was wondering if anyone might know a mod which would allow teens to have same option as adults not just in clothes but also hair, beard, etc...

Any hair made for young adults should also be available for teens since no changes are necessary to get them to work across those ages (the game automatically scales it). Each individual hair has to be set to work across the ages though - I don't think a mod would be possible to auto-enable them like that even though what works for YA should work for teen, hair-wise.

However, clothes don't work that way, and have to be made specifically for one age or the other; any mod to automatically enable one to the other would be a poorly made mod simply by its nature, as there would be gaps and mismatches along the seams and nothing would look right. Clothes have to be converted from one age to the other.