I logged on the other day and it was my birthday, I always set my birhtday in game on my actual birhtday btw. And there wasn't a villager outside my house, and nothing happened! I didn't have a party or get a cake from my mom! I got gifts in the mail and it was on the bulletin board, but apart from that, nothhing happened! My birthday was on the same day as the Fishing Tourney, would that affect it? Please reply asap!
I haven't heard if certain festivals would affect your birthday celebrations, and through checking game guides, apparently you have to have a high-medium friendship with a villager to have them throw a party for you. Maybe your friendship isn't high enough?
I've never logged in to ACNL on my birthday though so not sure what's going on, and it sounds weird that your mom didn't send you a cake at least.
You need to have a high friendship level with at least one villager, I believe. What prize you receive (birthday cake, table, shades, candle, sign, etc) depends on the friendship level you have with the villagers that show up on your party.
Mom doesn't send a cake, but she usually sends a letter with a gift.