I had mine at 31, (just one couldn't have another medically, likely would have chosen not to anyway) has been the best thing that ever happened to me. Life changed, but you have to look at the picture and decide if you want those changes or not.
For me I could list plenty of 'practical' cons - but the pros smash them all out the park!
Financially - initial reduction in pay for maternity, then longer term budgeting for childcare. Plus expenses for child (variable, but includes food, clothing (in particular the school ones), outings and the big ticket items (bed, matress, the usual baby stuff - depends on your network as sometimes a bunch of this may be gifted, once they aren't a new baby it won't be though)
Daily changes - never have a day off unless someone offers to have yours for a day/weekend while you're off work. Realistically in particular in young years you have someone to care and look after, take to places, do child activities with before, after, and on days off from work - so you don't ever really have downtime. Additionally you can't just 'pop out' unless you have matching hours with your partner, many work shifts to enable less paid childcare by covering yourself, so where you may have popped to the shops etc, you now will be at home when child is asleep, and if you 'pop out' with them, expect it to take a lot longer and to suddenly need to take a lot of stuff/pram/buggy/change of clothes etc
Impact/juggling of work - even with the best childcare if your child is ill you suddenly have to drop work/everything and look after them. Normally this is unpaid whilst you pay for the childcare
Mess/cleanliness - for me it isn't the mess that's made, it's just finding time to do cleaning. My son is actually very good at understanding 'one in before one out' with toys, but standard cleaning is hard to find the time when juggling work/cooking/looking after and keeping a child safe. If you're up with child getting them ready and taking them to childcare, then working 9 hours, then collecting and sorting a dinner/feeding child, then sorting bath and bedtime for child, there is no time in there.. so you end up either doing it when they are in bed, leaving it for days off, or hiring help!
There are plenty of other changes including things like a holiday never being the same again.
PROS
Love love and more love. For me I fell in love instantly. Cried at the birth, and have cried many times since. Sports days, nativities, first word, the first 'I love you mummy'. Literally nothing like it I have ever experienced, and I adore the time together, the teaching of life skills and educational things, seeing this little person emerge and develop his own personality and encouraging his likes/dislikes to develop organically and just watch with amazement. He has taught me more than anyone else has, I have done things I wouldn't have thought I would do as when they say 'I want to do X' and there is no harm in it, you go along for the ride and do something that without them, you just would have turned down. I've found it a really powerful experience and as a person I realised so much about myself. I've never regretted it for a second personally, there have been struggles, but I'd do it all again with him there 😊