Bath, I had a pretty free teenage life like you and have a 13yr old DD and 14yr old DS, both of which I am quite strict with as well.
Both my kids are not very good at calling me at set times and usually don't hear the phone when I end up calling them
I can't put my finger on why I feel this way really, especially considering I got to roam the shops and go into the city with my friends at the very same age. I never did anything wrong, just hung out with my mates and ate maccas usually.
I honestly think you are right to feel the way that you do.