Even if you have kids you will still have a 'void' in your life - only you'll be too tired to notice it! It will change you for the better and for the worse, the highs will feel much higher and lows much lower. As has been said before, everyone's experience is different, but if you go into it aiming to look after yourself too you should be alright!.
I have two little girls and would never have it any other way. I HATED the first year of no.1 as it was boring and tiring, I didn't know anyone and there's no getting off, but now when I'm laughing with (at?) my gorgeous five year old, I wonder how I ever lived without her and my baby friends are my best friends. Having children fulfils an ancient need - being wanted and needed and loved so much is wonderful, but of course it can at times feel suffocating.
But as they get a little older, it is so much fun! They make you laugh every day and make your heart burst with pride in a way you'd never feel about anyone else, plus you get to see the world again through different eyes (admitedly seeing those toddler groups over and over again is dull as ditchwater, but at least you get to have a coffee!) You'll become a cook, artist, gym coach, teacher, orienteerer, counsellor etc etc and learn loads yourself.
It will change your relationship, but not always for the worst - it is great seeing your partner adjust to a caring role and seeing them love your little ones as much as you do - you get loads more respect for them (although my husband left me after no.2... and the girls were incredible, I would never have got through it so well without them). Although he is back home and we are happy, I still see my unit as me and the girls, then him. I guess I'm saying you will never experience a tie as strong as between you and your children.
But that's my experience - I always say regret what you don't do not what you do.
You don't say how much family support you would have or how a child would affect finances - I think these factors influence your ability to enjoy parenthood massively.
Anyway, I'm killing time at work, good luck with whatever you do....