I wouldn't have a joint birthday or allow my friends boyfriend to attend my birthday party. AITAH?

So, this was actually an incident that happened a few years back, but the incident got brought up again and my friend insisted I was still in the wrong.

For some background, my birthday falls within the same span of 8 days as THREE of my other friends (20th, 22nd, 24th and mine on the 28th) who are in the same friend group as me and have been since we were 11. My sister also has her birthday within the same week (22nd), so since I can remember, I've always shared birthday celebrations with my sister and/or my friends as our birthdays were too close together to have separate celebrations. Since I was 12, me and my 3 other friends had shared birthday party's or celebrations every year - which was fine, but for my 18th birthday, I decided that I wanted my own celebration since it was a special age and wanted it to just be about my for once as every other year I'd shared the attention.

My friend - let's call her Katie, was upset that I wanted my own celebration and insisted it be a joint celebration as she couldn't be bothered to host her own at her house, and I refused as I had begged my parents to have the party at my house. I also wanted to be able to invite whoever I wanted, and if I had a joint birthday party I'd have to compromise on guests so we could all have who we wanted there. The other two birthday girls didn't really care even though they were the ones who had previously hosted our birthday celebrations so had more of a reason to complain that the one year I was hosting was not a shared celebration. Katie eventually got over it and celebrated her birthday separately.

Now, the next issue that happened was that I made my guest list and invited the people I wanted. Katie messaged me saying she assumed boyfriends were invited to which I said no. For some context about Katie and her boyfriend, they'd been dating roughly 2 months by this point and I had met him once or twice in passing and didn't really know him. I also already had 30 people attending and my house isn't exactly ginormous and getting my parents to agree to that many people was already a hassle. She got mad and pointed out that my best friends boyfriend was invited - so why not hers? I explained that it was because I knew my best friends boyfriend as they'd been dating a year and I had met him on multiple occasions whilst hanging out with my best friend and at other social events. She said it wasn't fair and got mad at me but I stood my ground. My other friend (not one of the birthday girls) who we'll call Claire, was also upset I had not invited her boyfriend. She and her boyfriend had been dating 4 years, but I had known her about 4 months, and had only ever once met her boyfriend - again I already had 30 people attending and didn't really care about random men I barely knew being there, just because they were dating my friends.

In the end, I ended up inviting both their boyfriends after a few people couldn't attend who were originally invited, just to end my friends griping, (also neither of their boyfriends stuck to the dress code which I insisted upon and was "my favourite things or some form of pink", which annoyed me as I thought it was rude and both of them just said their boyfriends wouldn't wear that even if they nagged so they wouldn't bother even though I said if they're going to nag me for them to come, they should at least follow the dress code and I would of been happy with any small amount of pink.) But when we talked about this situation recently, Katie stood her ground, saying that she believed I was still in the wrong and her boyfriend should of been invited in the first place and I should have had a joint party. (We are having a joint party this year for our 20th's mind you).

AITAH?