Yes, its young. Not necessarily too young. I was 21 when I had my first, had just bought a house, stable DP (now DH). We had good family support although not able to help with routine childcare as all GPs still working, although they had ds for days/overnight on weekends from time to time.
I worked in an office but left to go to uni as a mature student. I graduated at 27 and have been accelerating in my career ever since. Studying with young kids was difficult but no harder than working ft and at least my schedule was a bit more flexible.
My DPs were also young parents, as were my dad's parents. So my parents were grandparents at just past 40, and my grandad was a great grandparent at 60.
Like previous posters I was very much the youngest at every baby group and at the school gates and found myself quite unwelcome which was a shame.
Reproductively I was in my prime in earlier twenties, sailed through pregnancies and had lots of energy for night duties and chasing toddlers. Now I'm late thirties, kids are 15 and 17 and I still feel like I've got a whole life ahead of me.
Saying that, I would be concerned if my kids had children that young. Adolescence seems so prolonged for so many young adults, although not all by any means.