I got my tattoo when I was 21 and my father STILL doesn't know about it (I am 33 now). But I do not regret getting it.
The one thing to keep in mind is it needs to be something HE wants. When my friend and I went to get ours I asked her what she thought of the drawing of mine and the artist said...it's going to be on YOU forever, not her. I was like...good point.
I also thought long and hard about what to get. I originally wanted to get Dopey from the seven dwarfs, but thought ok a 70 year old woman with a saggy Dopey on her ankle....NOPE. So I settled for a nice small flower.

Anyway....my vote is YES. And going with him is an excellent idea, if he will let you.