My mother asked me once what I was doing to celebrate my 21st. I replied, "Doing? What do you mean?" at the conclusion of rather a chilly letter, and the subject never arose again. ;) But I suppose living in the same house as her makes the subject difficult to avoid.

Don't let yourself get talked into a giant extravaganza you don't want. Why not a quiet but lovely dinner at a good restaurant with those few people you really do care about? That would make quite a fine memory. :)