I've wasted two years on the wrong A-Levels??

I'm in year 13 at the moment, studying english lit, philosophy, and history, but I don't particularly like these subjects! I think they're interesting to read about but I don't like studying them in depth. I wanted (and still want to) take chemistry, physics, maths, biology, and economics in the first place as I've wanted to do a degree in chemical engineering for a long time, but I allowed myself to be persuaded out of this by my parents who love the renaissance subjects I've ended up studying and I've ended up with offers for an english degree from various unis. I'm very unhappy with this and feel like I've wasted two years of my life.
I've considered declining my offers and taking maths and science a levels privately, then doing the degree I actually want. Which I would be willing to and work extremely hard for, but I can't escape the feeling that I've wasted two years of my life? On the other hand, I could just go to uni this September and see what happens after that, but then I'm missing out on what I actually want to do. I am in such a pickle, advice?