Hi BW. You only have one sentence in your posts so you should ask 'Is this correct?' or 'Is it correct?'. This is better as it means 'this sentence'.
I assume you mean birthday. Birthday is not abbreviated to b'day. If you say b'day then it sounds like bidet and believe me you would be a bit of a pervert if you watched someone at a bidet! Also, birthday is not a place you can be 'at'.