Coming from my 7 and 9yo, it would sound bratty but age appropriate. At 70? I'm trying to be understanding, but my initial reaction would be similar to my kneejerk response to my kids: well, we can just not celebrate your birthday, if it comes to that. If you want tosuggest something more reasonable like a party, I'm happy to oblige. If not, tough. Have a fun birthday.
Hopefully I'll have simmered down before I actually said something, though.