I think it's reasonable at a year to have a serious conversation about how you both feel about marriage. Not necessarily with each other but how you see it working, what roles each partner plays, kid raising, expectations, etc. just to see if you are on the same page about things. If at that point, you and your partner are in a place where it feels natural to talk about marriage between the two of you, then go for it. If not, wait until the time feels right for you.
I think in my personal experience (speaking for no one else here), it feels like you are expected to be on someone else's time table. If you've been seeing each other for X amount of time other people start questioning and asking what's wrong or when the ring is coming, blah blah. It gets difficult to hear what the rhythm of your own relationship is telling you. It's hard to shut out the backseat drivers but only you and the one you're with can make the decision and don't hesitate to tell others that they will be the first (second, third, whatever) to know when you make a decision but until then, butt out!