As said, you are completely right and this way they learn how to manage their own life. That's also the way my parents have done it with me and my siblings and it was a sometimes hard, but a good and working way.
Next months my kids will be 18. My daughter is still going to school and I think she will go to the University, but we are not sure yet what she wants to study. My son is still searching for something he likes and we try to help him as best as we can.

Cheers and !BEER