TIFU by "proposing" to my girlfriend as a joke and now we are accidentally engaged

I was at a home improvement store with my girlfriend roleplaying as boring suburban homeowners because we think it is hilarious, and I jokingly said "I just want to build a life with you and maybe tile a backsplash someday" she laughed and said that almost sounded like a proposal, so my dumbass, thinking I was being so clever, grabbed a random washer ring off the shelf, dropped to one knee in the lighting aisle, and fake proposed as a bit, except she said yes with full teary eyed sincerity, and now I am just standing there holding a rubber washer ring, her mom is already blowing up her phone asking if she can announce it on Facebook, and I still have not told her I did not actually mean it because at this point I am 72 hours deep into a bit that has somehow spawned a group chat, venue pricing research, and my dad asking if he should wear a tux, so I guess I am either getting married or dying on this hill please send help or cake samples. TL;DR: Turned a joke about tiling backsplashes into an accidental engagement, too deep in the bit to back out now.