Should I ignore my sisters birthday?

Every year nobody wishes me a happy birthday except one of my 5 siblings, which wouldn’t bother me except they also ignore my sons birthday. Every year i try to be the bigger person and on their birthdays I’ll call or something to wish them a great day and all that, but it sucks when a couple months pass and they can’t return the favor, and they know when my birthday is. Is this petty? Just over trying.