By the number on your screen name, I'm guessing your 16. So are you studying GCSE or A levels?
If you're studying GCSEs right now, I would say it doesn't matter. Then study something like Art textiles, Textiles or Art. And even though the above made fun English will always be a good thing to study, no matter what you do!
A levels will be a bit more difficult.
I would guess the best way forward if you're in A levels then I would say, maybe go to college after finishing your A levels and study a BTEC in Art or Fashion. Its the long way round, but if this is what you want to do it will be worth it.
Also maybe get a job in a clothes shop, work experience will always look good on a CV!
But remember this is a lot of people's dream job (Including mine) You have to be the best of the best to get into the business, have your reserve careers!