Disowned over a tattoo

I always knew my mom wasn’t a fan of tattoos but her rule for tattoos and piercings where if you’re 18 you can do what you want. Or so I thought since almost all my older siblings that where outta the house had them (my half so not her bio kids) so when I turned 18 my friend surprised me with getting tattoos together (not matching) I got a string of forget-me-nots on my upper ribs. When I went home that night I found out a relative had passed so I knew it wasn’t a good time to bring it up. I few weeks later I brought a “hypothetical” question about getting a tattoo and she flipped out and told me she’s disown me if I ever did and a few more nasty words. She told me never under her roof so I was going to tell her when I went to college but again the same thing happened. So I never told her now at 20 in college I got a big shoulder to shoulder tattoo my dad and boyfriend paid for it (my parents are divorced). My mom has now been commenting about how she knows I’m going to get a tattoo someday and asking if I have but I’m almost 100 percent sure she’s still against them. Any advice would be amazing.