Tattoo Location

Whuts up Im gettin my FIRST tattoo real soon and even though its not my main peice tattoo im real excited. Im gettin the words desiderata tattoo'd on me. But I just cant come up with a decent spot! I weigh 160 pds and im 6'1. So im fairly skinny, now, if I get desiderata on my forearm or inner bicep then gain say 15-20 pds will it stretch alot?? I assume I dont have to worry about stretching when it comes to the forearm, but what about the back of the arm close to the triceps. Is there anyone here that got a similair tattoo on there arm then Gained some weight through wieght training?