You have my complete sympathy, em
I have twin daughters who both wanted theirs done when they were 17. I said my view was that they should not have this done and I would be very concerned, for all the reasons you give. When they were 18, they both went to have them done - never on view, as they didn't wear clothes that exposed their abdomens. They got through university, got jobs, settled down, and lo.....at the age of 27, first daughter is having her twin babies and realised that this piercing is giving her trouble - had it removed in A and E. Second daughter stops wearing hers as a result.
They also had tiny tattoos, concealed on shoulder and abdomen respectively. First daughter to have piercing removed is now having injections every 6 - 8 weeks to obliterate the tiny tattoo without leaving a mark or pigmentation. Why not laser? Quote -'it's very expensive - at least these injections, though they take longer to complete, cost a couple of HUNDRED pounds less, mum.' On seeing the glint in my eye, she said 'don't even say it.'......told her so....