I don't agree with your father, sorry. I don't think there's anything wrong with dating in our teens - we're genetically programmed to look for a mate in our early to mid teens, so it's perfectly natural. I had my first boyfriend when I was 16, and I was with him for two years. I can see nothing bad in it - he didn't prevent me from continuing with my education, and I was still able to finish high school and go on to university and obtain a degree.
From seeing other people who have been oppressed by their parents, and comparing those people to myself and those who had a more liberal upbringing, I can only conclude that being allowed a certain degree of freedom to make one's own choices is by far the healthier option. In our teens we are learning how to make our own decisions, because we are old enough to do this. And making mistakes is how we learn - dating different people is how we find out what kind of person we are compatible with. Dating in our teens allows us to practise getting to know people on a more intimate level. When we oppress this natural instinct, and wait until we are in our 20s to date, then it becomes more difficult, and a more nerve-wracking experience.
My answer is just based on my experience and what I have observed in others.