One month ttc

I came off my BC at the first of the year. My period isn’t expected until Monday 2/5. Here lately I just haven’t felt right so I tested at 8dpo bfn. This morning is my husbands birthday and I thought I’d try again 11dpo and I believe I got a bfp. Can this happen this fast?? I’m almost in shock and disbelief. Can you test positive this far from your expected period date? Help!! I don’t want get my hopes up cause honestly I was expecting it to take longer than this lol comments very appreciated!