I wouldnt be too stressed mate you are young....17....lots of time, last thing i would do is rush into something or get stuck in something that doesnt interest you etc.
I went to uni, straight science, into anatomy and physiology into health sciences and public health and in the end finished (1 year extra from my mind changes etc) and even at the end had no clue what i was going to do....happened to fall into a great private sector job and still there.
I remember being in a chemistry lab one day and it was all getting too hard lectures were over my head and the prac classes i fumbled through, lucky I'm 6 foot so i could look over ppls shoulders for answers lol....end of semester and i had failed chemistry and another i think.
That was the eye opener to me thinking...WTF am i doing this for when i don't like it and don't want to be a lab rat all my life....so i switched courses.
Similar to what you want to do.....everyone will have an opinion and have advice for you.....take it but still the decision is yours, don't let anyone pressure you either way, if it doesnt work out you learn from that and move on, lifes full of mistakes and difficult choices, as long as your happy, have enough cash to live its all good, like others said, people make career changes in their 30's to 40's now that takes some guts as generally its not just you to worry about its your families livelihood.....apparently the average person changes their career upto 3 times during their lifetime.
good luck mate.