A cautionary tale Op.
Many moons ago, I was your like your sister, and my sister was just like you.
I got engaged at 19, married at 20, we had good jobs, I got pregnant easily, my DH climbed up the ladder at work, we had a huge house and plenty of money.
My sister, on the other hand, was single for a long time, had no money, a tiny terraced house, she also had a horrible first marriage that ended, and then when she did meet someone else, she had fertility problems.
She absolutely hates me, and it all stems from jealousy. The thing is though, that my fairy tale life fell down around my ears, when I found out that my DH was cheating on me, and had been the whole time (multiple women). We divorced and I had to start over. I have built myself back up, but obviously nowhere near to the financial place I was before, but I've been lucky and now have a lovely DH.
My sister who was never well off back in the day, has since done well at work, married someone who earns well, they have inherited loads of money, and they now live in a £500k house with no mortgage. They overcame the infertility issue and have 2 lovely DC.
BUT. Because she was so jealous of me for years, she ruined our relationship, and we are now No Contact.
She got everything she wanted in the end - the nice DH, the big house, the 2 healthy DC, but lost her only sister, by being jealous and nasty when she thought she was the under dog.
The whole thing is such a shame. Don't be us.