3 years for A levels- will it hold me back?

This year at AS I studied biology (B), chemistry (B), french (C) and economics (C). I chose to drop economics straight after the exams as I hated it which meant that I had to continue with the other subjects regardless of my grade. I hoped to achieve higher in french as my grade was very close to a D. Over the summer I have really been dreading french and as I don't enjoy it don't think I will put the effort in
to improve my grade.
I was hoping that it would be possible this year to study A2 biology and AS chemistry along with 2 new AS's. So that next year I can study the A2 courses of chemistry and the other 2 new subjects.
Do you think taking 3 years to complete will hold me back in regards to uni???

Thanks, my mum keeps saying that it's a waste of time but I was planning a year off before uni anyway so this would just be instead of a gap year. And also I would get 4 A levels and 2 AS grades. I haven't enjoyed this year at college and have felt really unhappy so I don't think she wants me to be like that again but I hated half of my subjects so that might explain it!! I hope to be much more motivated this year as I know that I could have done sooooo much better this year if I had worked harder