Just read this thread through and really enjoyed it - very interesting.
I don't know if it's any "harder", parenting teenagers than parenting little ones but it is certainly different...
Here's my two penn'arth:
The baby stage, I loved. Give me a baby and I'm in my element. I completely "get" babies and found the whole thing very natural, easy and enjoyable.
Toddlers, however, were a whole different ball game. As alien land, really. Often found it very challenging and sometimes downright miserable. Don't think I could do it again, to be honest
Teenagers - even WITH all the teenagery stuff, I still think this is my favourite stage of all - or at least on a par with little babies.
A very small selection of "Downsides" of life as a Mum of teenagers for me would include:
Arsey, bolshy behaviour
Spectacular self-centeredness
Untidiness/ general thoughtlessness around the house
Worries over nights out/ drink/ physical safely
Worries over sex/ morality/ emotional well-being
Endless angst over how strict/ liberal to be - "EVERYONE ELSES MUM is letting them! Why do YOU always have to be so GAY?!"
Sleep deprivation because of having to pick them up late/ not sleeping properly until they are in
Constant shifting of goal-posts - what is acceptable to you and them changes and changes and changes again, very rapidly
Knowing it's your job to prepare them for an independent life but feeling inexplicable, raw pain as they ebb away from you towards that independent life
Riding the hormonal roller-coaster with two DDs. PMS is really quite extraordinary to observe when you're not in the starring role!
Cost! The cost of teenagers takes my breath away. I have two and I am staggered by how much they cost us. Makes the cost of younger children look very good value in comparison!
However badly they behave, you have to dig deep and find it in yourself to behave better. However awful they are, you can never walk away, you have to work out a way forward. It's really, really hard sometimes.
When they're little, you have ultimate control because you're Mummy - whatever you say or do. When you have teenagers, if you behave like a prat, they will laugh at you in a "God, you're pathetic" sort of way. If you behave like an even bigger prat they will walk out: "I'm going to stay at Kate's house". Cue the horror of the humiliation of knowing Kate's Mum will be there with the cup of tea while your DD tells her how unreasonable you are...
A very small selection of "Upsides" of life as a Mum of teenagers for me would include:
They are SO much fun! SO full of life and passion and drama and their lives are so packed and exciting and there's always so much happening and it's all fast-moving and quite exhilerating. And there's ALWAYS something new...
We love the same music - dance around to Rihanna and pinch stuff from each other's iTunes. Still shudder to think how many times we used to have to endure the wheels on the bus in the car...
Ditto films - forget all those cheesey kids' films - we can go and see The Kings Speech/ Never Let Me Go or whatever and then talk about it over pizza
Long journeys are a doddle - see shared music taste above and stuff like Facebook on phones to fiddle with
They can be great company and same goes for their lovely friends. They're fab, interesting people and have lots to say and contribute and they make us laugh - SO much fun.
Shopping - love going shopping with my girls - they love clothes and makeup and girlie stuff and everything looks amazing on them
They don't think to offer to do much in the way of housework but will hoover without complaining if asked
They both cook. They quite often like the look of a recipe in a magazine and ask if they can make it for supper ("why, yes!")...
They're competant at lots of stuff so it makes playing tennis/ a board game/ whatever with them good fun, because it's a real and fair game, if that makes sense.
As cat64 said, you can do your own thing, live your own life and not have to arrange child-care or drag everyone with you.
They can travel independently
They CAN be really thoughtful and sweet and lovely and cuddley still!
Overall, I'm really enjoying the teenage years... I do sometimes wish I had had another child but then I do often feel that the financial cost of the of the two that we've got is quite daunting...
Good luck with your decision, OP.