Welp since your 14 you just gotta do what we all did....... abide by your parents rules. It's just the way of the world, you'll be a little older soon and have more control over your own choices in no time. Things will change in just a couple years, most parents lighten up when their kid starts looking more and more like an adult and less like their baby they still think of you as. BUT! If they are allowing you to learn Muay Thai then I would suggest practicing it somewere else like a park or a community centre or even get a gym membership with a gym that has a room available for you to use and practice in. If your allowed out of the house at certain times of the day then go practice somewere else.
Damian Mavis
Honour TKD