I do agree that her life decisions should not affect yours. There is no such thing as fair. You both are adults and should act like it. It sounds like your parents have spoiled you both.

Reconsider what exactly??

I am kind of on the fence about this tbh. 1. If your parents didn't celebrate her birthday at ALL just because she was pregnant, that seems like top level douchery. She's pregnant, not dead, it just means she can't drink. 2. What kind of trip are they gifting you? If they did nothing at all for her and are giving you a $5000 Hawaiian vacation, I would be ******* pissed too, even if it's totally a person's choice on how they spend their money, really obvious favouritism is never going to go over well... 3. Throwing a tantrum at however old she is, isn't pretty regardless of the situation, so she needs to dial it down about 100 notches. So yeah, I feel like I need a little more info here.

I could be way off here, but you both sound like a couple of spoiled children. I hope your parents did help her out if she was pregnant and unwed, but if she was married, if celebrating her 21st was such a huge deal, perhaps she should have planned her pregnancy a bit better. Hard to be objective when we don't know all the details.

I’d feel bad for you if your older sister went on a trip then wants to change the standard, but she didn’t. You are an adult, life isn’t fair... get over it.

On the one hand, you shouldn't be punished for your sister getting pregnant. On the other hand, you'r parents don't owe you a trip.

I feel like you say this like everyone's parents send them on a trip for their 21st birthdays. Just gonna say my 21st birthday was a beer with my sergeant after a 12 hour guard duty shift before crawling into bed to cuddle with my wife and daughter. So even if you don't get the trip meh worst things.

1. A tantrum is too much, 2. She has a right to be upset if your parents didn't do anything for her and 3. I don't think they should pay for the whole trip, I mean come on your 21 time to be an adult. I'm 21 and have to pay for everything

She sounds like a spoiled brat. I do wonder, though, why your parents are paying for either of your birthdays at this age. Still, that's their right, and turning 21 is pretty special. Just don't get stupid drunk. ;)

Go on the trip and tag her in all the photos