There's pros and cons to having DC youngish (pre 18 is definitely worth avoiding if possible I think) or older. Neither is 'bad' per se.
In my close friendship group there's a wide range on this issue. The ones who were younger mothers, were of course still relatively young once their DC were going off to uni, leaving home & did/do some things that those who had DC older did pre DC.
As a result some of these friends (we're all within 5 years age of each other) already have grandchildren, and some are still in the early toddler/infant school stage with their own DC.
Some DC were planned, some weren't - but the age of the mother at the time still varies greatly. There's been a few late surprises, and some struggled to become mothers by personal circumstance or due to medical issues.
Similar to the op I chose to be one of the younger ones, due not just to where I was personally, but because medical issues meant I felt leaving it later was too big a risk - turns out I was right as even though I was undiagnosed at the time I started ttc I do have a condition that makes conception and maintaining a pregnancy difficult. I've had 2 mc losing 3 babies, have had to have several surgeries and treatments, dds pregnancy was high risk and carefully monitored and even then we both still almost died during the birth. Due to 2 other conditions that are extremely rare, only become apparent during/immediately after birth and could not possibly have been predicted. Sadly one of these also meant I had to make the decision not to risk another pregnancy leaving dd motherless.
Women have first DC at different ages for all sorts of reasons.