Start Cutting the Apron Strings....@ 19 almost 20??

I'm so confused here.. And not because I have Chemo Brain or Fibrofog... At what age do you let your baby start being an Adult. Or at least a young adult, where you sit back just a little, and let them make there own decision's without interfering?? At what age do you let your young adult go on a road trip 2 hrs away to visit a friend.. A guy friend???
I love my daughter dearly, and I trust her to make right decisions, and to be able to tell the difference between right or wrong. And if she does make a wrong decision.. then she's smart enough to call mom..
When I was my daughter's age, I was already married.. Thank Goodness she's not.
I think that I am doing a pretty good job of letting her have her own space, make her own decision's with minimal input from mom.. It's actually my ex-husband her Dad that is having the hardest time.. He thinks that he should be able to still tell her what to do and when. And his word is the law..
I actually think at times... NO, I know at times that he is Verbally Abusive toward both our children... and it just seems to get worse the older they get, the more freedom that they want, or desire.. just kills him. He just can not handle it, and he will do or say whatever he thinks will get them to obey his wishes... I have talked to him about this many times...And there is no stopping him... And if I step up and say, well I think they should be able to do this or that, or whatever it is that is in question.. The first thing out of his mouth is, don't you care about your children??
Yes, I do.. Thank you very much... I feel that I love my children enough to let them be who there gonna be, and not try to shape them into what I want them to be.. But, anyhoo... that is an ongoing struggle with the ex..
The question is... Am I being a bad mom if I just let my daughter drive 2 hours to visit her boyfriend....
Now don't think that she won't be getting an ear full as she's going out the door ... Do you have your cell phone, did you get gas, do you have enough money, do you have your directions, and so on and so on... And your sleeping on the couch... RIGHT.....
Am I being a bad parent for having enough faith in my parenting skills, to believe that I can start cutting the apron string.. at least a little??