Yeah, yeah. You only want to hear that you're right, so of course I must be "negative" or "insulting." No, no. That won't fly.

You are making grand uninformed plans when there is absolutely no need to. This is what your father is trying to tell you. Maybe you should listen.

You said you'd never commuted by bike and have very limited biking experience. Does it really make sense to commit most of your earthly funds to biking, then? Absolutely not! You could borrow a bike for a while. Rent one if you can. Buy a used bike if you must. You might find that after one commute, that you totally hate it and will never do it again. Or you might find, like most of us, that bike commuting can be an occasional replacement for a car... but that you really do need both.

Pull your head out of the clouds and stop worrying about "taking full advantage of my youth". Whatever that even means. Use some common sense. Your father would like that.