As others have said it might not necessarily be criticism, just possibly surprise.
My best friend from university married her boyfriend the year after we left uni (aged 22) and had had 4 children by the time she was 29. It's fair to say that at the time I was very surprised by her choices, we had studied so hard and come so far and suddenly her career plans were completely out of the window. As it turned out she was and is blissfully happy, which is perfect, but still, she never did get around to pursuing the career she had dreamed of - but then who cares as I said she is blissfully happy so those old dreams are irrelevant I suppose.
I was also together with my DH at 22 (although we didn't marry until some years later), but I suppose I followed the more usual pattern in that I pursued the career path and luckily was very successful, traveled the world etc etc before having DCs when aged 32, 34 and 36. In retrospect though were my choices were better? I'm not sure that my career made me happy exactly, it was a LOT of stress etc and I was glad to give it all up just before I had DC3, but for me it was the right choice I am VERY proud of what I did and happy I had all the experiences that went with it.
In the end we pretty much ended up in the same place - lots of children, stay at home mothers, very happy!
You are happy, that is the main thing, try not to let other people bother you - you will meet lots of lovely new 'Mum' friends. With your old friends - well they won't understand babies etc, try not to hold it against them. I certainly didn't get babies at all at that age, I remember visiting my friend when her DD1 was a couple of weeks old. My Mum had told me that the one thing I must do was to ask her if she wanted to have a rest, so I did, she jumped at the opportunity and went to bed leaving me (who had never before even seen a new born baby) holding this little sleeping bundle and scared even to move and reach out for the TV controller in case she woke! It was a shock! Our lives undoubtably did diverge, after but we managed to remain good friends. Try to keep in touch with those friends that you care about, but on a different level, possibly as a much needed escape from all things domestic once in a while, and secretly look forward to the frisson of schedenfreude when they finally catch up with you and have children of their own.