This question was recently asked of me online by kaykay0.
Unfortunately there is no one answer to this question as there are many variables involved. For one, weight gain and pregnancy have strong influences on the way a tattoo ages. Obviously getting a tattoo in areas where skin will expand due to severe weight gain or during pregnancy will have a negative consequence on the tattoo. While your body is still growing at the age of sixteen, your height has pretty much settled in and any further growth will be in body mass. I have seen people gain a hundred pounds without showing any severe indication of ‘stretching’ of the tattoo. Overall, I don’t see any real reason you should be concerned with getting a tattoo at sixteen.
A more realistic consideration would be in the choice of tattoo. I find most people who get a tattoo at such a young age eventually live to regret their choice as it is seldom made with long-term thought into the design.