This is a very personal decision. Do I think everyone is "cut out" for being a parent? NO. Reading your questions did make my mind wander a bit, though. Not to be ugly, but it sounds like you are afraid kids would "impose" on your life. They absolutely DO impose on your life...they, in fact, become the center of your life!
I'll tell you my story. I got married when I was barely 19. My dh and I had been together since I was 16, he was 19...we were & still are best friends.
8 months into marraige, we found out I was pg...not really planned, but not unwanted either. We both wanted kids eventually. So, I had my dd at the age of almost 21. We had our second child 2 years later, our third two years after that, & our 4th and last 2 years after that.
We are happy. But not everything is roses. There are days where I want & need to be alone without the responsibilities of parenting. Sometimes the grandparents can help out & give me and my dh the time we need for ourselves, sometimes they can't. So there are times that I would like to have alone, but can't. But it doesn't make me resent my kids or wish I hadn't had them. There are also days where I ask, what did I do? What was I thinking? But then they will do something so incredibly cute or wonderful that the bad goes away. There's just a love there that you can not explain & you won't understand until you have a child.
I do worry about what if they don't turn out to be good people. My answer to that is to do everything in my power to guide them in the right direction & leave the rest to God. I have one son that we have trouble with...he's a great kid, has a lot to offer but he has issues with responsibility & respecting authority. He's only 7 so we have time to correct this behavior, thankfully. My dh and I have to work together parenting or it just doesn't work for us. It definitely takes the both of us (along with a lot of prayer!!!)!
You're young. You have time. My advice is to search your heart, talk with your dh. If you really don't want kids, do NOT have them! Do not have kids just b/c your parents want grankids or b/c all of your friends have kids. That does no one any good...you will be miserable, your dh will be miserable, & your kids will be miserable.