tatoo help

heey im 15 and i really wnat to get a tattoo on my loer stomach, i fianlly got my mothers premission but now there is just one thing holding me back. ppl keep tellin me that if i get my tattoo on my lower stomach it will get ugly and strechted when i get pregnant. i realy want to have a child in the futur but i don't want my tattoo to turn into and ugly blob. will it go back to normal after i give birth and loose the weight? i have been trying to find some information on it and they say that it depends on what you get. i want to get a small butterfly or a heart, will those become distorted? i also read that strechmarks are hereditary, my mother had a very big stomach when she was pragnent with me but she had absolutly no strech marks. pls help me!! i need to know wuts going to happen to my tatoo! ps. i have my belly button peirced as well, wut will happen to that??