Thinking back to my childhood birthday parties, I can't remember if my aunts were there or not, to be honest.
Kids' birthday parties generally suck for adults so team SIL here.

My aunt has always been a second mother to me. My husband's aunt was like a fun big sister (only 12 year age difference.) But my children's aunt is that woman they only see on Christmas who doesn't even say hi to them because she's not a kid person. I'm allowed to have feelings about that and I keep those feelings to myself.

Get a grip OP. She may not have have an engraved invite to her friends party, but clearly it’s planned enough that she could immediately tell you she is a maybe. It’s not like she RSVPed yes to you and is cancelling at the last minute for a blind date. The kid either won’t know or won’t care that his aunt isn’t there. Missing one party doesn’t doom their future relationship - but pitching a fit and trying to guilt her into coming might!

My sister doesn’t have kids and has very little interest in spending time with mine. A few minutes of a fun activity for a photo op and that’s plenty. She lives across the country but still doesn’t want to spend more than an hour with the kids when we’re all in the same city. And that’s fine!! Obviously I wish she cared about them more and wanted to do fun things and make fun memories. But she doesn’t like kids, mine included, so whatever. Trying to push a relationship over her objections won’t help.

Anonymous wrote:Family means nothing these days unless it’s convenient and fun for you. What an embarrassingly childish and selfish culture.

Friends means nothing these days unless it’s convenient and fun for you. What an embarrassingly clannish and selfish culture.

Super cool how OP didn't give details but everyone is lashing out at each other based on their own imaginary parameters.

People, it's not the baby's 1st birthday party. It's the mom's 1st anniversary of having a baby party. Obviously the baby doesn't care.

Anonymous wrote:Honestly…I don’t really blame her. The reality is if she attends every birthday, every this or that until she has a kid of her own, we all know there will be no reciprocation because op will be too busy, no longer interested in that younger stage, and the aunt will be left disappointed she missed out on stuff with her friends and wasted all those Saturdays on dumb kid parties.

Projecting much?

Anonymous wrote:OP, you didn’t answer how old your child is or what kind of party it is. If it’s a party at a bounce house that’s different than if it’s a small family party at home. And prioritizing family does not mean, for some of us, that everything else will always and forever give away when it competes with something involving family. She can take him out separately to celebrate by going out for ice cream or something. Or not. I wonder if something else is going on here with you and this person?

OP hasn’t answered any of this, has she?

Anonymous wrote:Where's the godfather? Will he be there?

Single godmother. Tragic story.

Your child will be traumatized for life!!