I'm another one who found the baby stage pretty miserable I'm afraid! We have 2 teenaged DDs, and they are my very most favourite people! They are interesting, funny, kind, all-round wonderful human beings - we feel incredibly lucky to have 2 such fantastic people in our lives.
That said, there have been a few tricky bits since they hit their teens. Friendship dramas, anxiety and academic pressures have all caused some concern over the last few years, but we've always managed to maintain an open dialogue with our girls, and they have always (so far, at least!) been happy to talk things through with us and listen to our advice. Our eldest DD is gay, and came out to us when she was 13. DH's closest friend (and DD1's Godfather) is gay, so DD1 knew we would be supportive and that whoever she is attracted to is of no consequence to us as her parents, but I know that for some, it could be a really difficult thing to navigate.
Having teenaged children is a whole different ballgame in comparison with the baby and toddler stage, and I think my 'parental skill set' is far better suited to older children than to little ones. I know DH and I are 'lucky' to have such well-mannered, hard working, well behaved DDs, but I believe that it's at least somewhat a result of how we have parented them. I think that if you can instill the basics when they are small, and you foster an open and honest relationship with your DC, then when they hit the teens, hopefully you'll be in a good position to deal with whatever drama your teenager dreams up to throw at you!