I received a birthday card from my sister today. My birthday was 2 months ago

I didn't expect a birthday card from my sister, maybe a text?  A birthday card two months late seems odd?

Should I be bummed she doesn't know my birthday?  Do you reach an age where a card, or family remembering, doesn't matter or isn't expected?  I sent her a card for her July 9th birthday, which I absolutely know is her birthday.  It's hard enough being over 1000 miles from home.