As an individual who has a giant back tattoo. My suggestion is to make sure you absolutely know what you want, and that it means something to do. One issue of guidance that a friend told me for when I was about to get my first tattoo. Is to wait at least 1 year after deciding on exactly what you want to get. Then if you still feel the same in a year; get it. This allows you to remedy over the thought of the tattoo, and then confirm if it's exactly what you want.
I can't tell you what to get, but.. When you find one take a picture of it and put it as your phone background for about 30 days, if you still like it after that and haven't changed your background then you will be sure. :)