Well I would not wait to much longer.....Especially if you don't have much or any amatuer experience....At 25 if you start now and take it seriously you could have a go at it....Boxers are lasting longer now not like years ago when 30 was considered old by most......Either way if you want to take it up seriously or just as a hobby have some fun....I know amatuers in their mid 30's who box as a hobbie