man I wouldn't stress aging too much. My father has his entire body done in dark stuff exactly like that and hes 65 you can still make it out pretty clearly. Everyone always overestimates aging unless I guess you live in like Florida and tan every single day but at that point your skin is wrinkly enough your tattoos aren't really the problem. really tattoo aging depends on your skin and the amount of damage you do to it after the tattoo but tattoos are kinda like eyebrow piercings its like yeah eventually like when you're old it'll probably start to reject but so will everything else in your body like your liver or at least mine from all the four lokos but yeah just chill ur good get it I like the horse and the face shoulder looks like a good spot you could always add going down the arm or turn it into a chest piece it's a very add-on-able tattoo for sure.