I don't think it's wrong to think about a future with someone so early in a relationship, but at the same time, I do think it's healthy to be realistic about it. A year is not a long time to really get to know who someone is beyond the initial excitement of a new relationship. Even if you've known each other for a long time, being friends is different than being in a relationship, particularly one where you're living together and dealing with all the mundane things that go along with having a family and a home. The fun, spontaneous exciting person you first get to know when you are dating is not necessarily the person you'll be spending years of sleepless nights with when you have a small child or the person who will need to remember to empty the bin or wash the dishes or pay the bills. The little challenges and cracks in a relationship often don't show until the stresses of the mundane start to pile on top of you (and nothing is better at piling them on top of you than having a child together). Being co-parents means you'll be stuck with each other for the rest of your lives, even if your relationship doesn't work out. You'll always be in each others lives, having to figure out how to split your child's time between the two of you, and dealing with potential step-parents raising your child. It's a huge commitment, and if you don't think you're both in a place where you would go and get married today, then I would ease off on the rush to have a baby until you're more sure of what the future holds. You obviously don't need to be married to be together and have a baby, but if that seems like a big step and more of a commitment than either of you is ready for, then a baby is an even bigger one (at least a marriage you can annul and go on and live your lives as if nothing ever happened).
You have to both be totally in this for it to work and if he's backing off, it could be he just doesn't feel ready to make that sort of commitment so early in your relationship, which is totally reasonable. I would just ease off and enjoy your time together (time you won't really have much of if you have a baby) and see where things go. You might find in time that you're both totally on the same page and ready to make such a big commitment, or you might find your initial impression was totally wrong and he's not the sort of person you would want to commit to raising a child with. Certainly, when I was 21/22, I thought I'd met that person too after only a year and wanted to have a baby. We waited and didn't and it turned out, years down the road, that he was a complete lying cheating jerk. I'm so glad I didn't rush into things before I really had a sense of the person I was rushing into them with. I didn't meet my husband and have our first until nearly a decade later and that ended up being perfect. I am so much happier than I ever could have been and I have my daughter because I waited and met someone who I actually got to know and live life with before we jumped head first into parenting.
As for the endo, don't let it put pressure on you either. One of my best friends also has endo and suffers quite badly with it. She waited until she was 39 to get pregnant with her first (not because of fertility issues, just because she was traveling and working and enjoying life and not settled down yet). Then she met someone and it all happened really quickly. Her daughter was born just after she turned 40 with no issues at all. So it doesn't necessarily need to be a factor at all.
