Don't worry too much about the pain related to tattoos. I have 6, and I must say the worst one pain-wise was the one I have on my stomach. For the most part, the outline is the worst, and the shading is almost a relief.
I at one point was afraid of needles, and getting my first one really helped me get over that fear. Now, they're an addiction, yet another expensive hobby aside from my herps. *L* I also find them, in a sense, to be rather relaxing.
That is a REALLY awesome drawing by the way; that would look pretty good on an upper arm in my opinion. Plus, getting your first one on the arm always seems better for people, as it tends to hurt less. I'm an absolute dragon FANATIC, so, I'll be getting plenty more of the creatures inked on me soon.
Everyone is different in how they react to getting tattooed, hopefully yours is a pleasant experience. Good luck!