For full disclosure I had a baby at 20 with my partner of (at conception) 9 months. "Baby" is now 8 years old. :)
There is never a right time but it's not fair to pretend it would be just as hard now as in 5 or 7 years' time. It will be harder now. It will throw your relationship into incredible stress, it will be a financial strain, and having a baby out of step with your peers is difficult because it alienates you from your friendship group both now and again later when they begin to have children. It's effectively ending your twenties pretty much now. Of course, it's not quite as dramatic as never being able to go out again, but the reality is that you won't be able to attend all of the events people plan, you probably won't want to do the same things they do either, so you'll end up out of the loop, you'll miss things, your friends often get frustrated at your lack of contact because they don't realise how much of your time a baby takes up yet. And it's difficult to make new friends because you don't fit in with either the teen mums or the stable 30something crowd, and there's not much in between. Even if you wait and have your second later, you're still out of step because you're not having your first. So you will have a different experience. That might be important to you, or it might be a minor detail.
There's no reason that a termination would make pregnancy more difficult to achieve in the future if that's still what you want. It's very likely that you could terminate this one and go on to have babies perfectly normally and healthily later on. (If nothing else, you've proven that you get pregnant easily!) But on the other hand if you think that the experience of pregnancy now and a potential abortion would lead you to want to try again very soon e.g. within a year or two, then it's probably not going to make much difference, and you might as well go ahead with this one. It might be worth it to give yourselves longer.
One point I will mention is that my relationship was not very supportive and we ended up splitting up. I am not saying that this will happen to you or even that it's likely to happen, but the whole experience has made me realise how important it is to be with the right person when it comes to the time to have a baby. Everything else - timing, age, gender, financial situation, it just pales into insignificance compared with choosing the right person, even if you end up going it alone. At 8 months into a relationship, you're effectively taking a gamble on this. He could be really great and as supportive as he is promising now and everything will be fine, and of course, you'll find people who love to tell you about their situation where this happened but on the other hand he could have traits which come out later which make co-parenting difficult or just miserable. It's honestly not really predictable but I would caution that if you've ever noticed anything which vaguely hints at red flag-ness (controlling behaviour, insecurity which affects you e.g. jealousy, criticism, any alcohol or drug or violent tendencies even if not around you, rushing the relationship along quickly, being tight with money, etc.) to think really, really carefully about whether you're sure. Good "green flags" are things like how supportive he is of you when things aren't going his way or when your attention is focused elsewhere or when you're vulnerable for some reason, whether he takes on equal responsibility for household stuff and whether he supports your dreams and ambitions rather than just complimenting you in ways which keep you where you are. But even with all of the green flags in the world you can grow apart. However a respectful, healthy relationship has more chance to turn into a good co-parenting relationship whether you stay together or not.
Of course it's not an easy decision - I've been typing this on and off for a while so I expect someone has already said, but have you looked into pregnancy counselling at all? (You might also find you get more/a different spread of responses if you post in Pregnancy Choices or Relationships or even Chat, as this forum is mostly read by people who are currently pregnant either with a planned pregnancy or one they've definitely decided to keep).
Very best wishes and good luck for whatever you decide!