When my brother came out, he wrote my parents a letter first because it was such an ordeal for him to tell them. My reaction when he told me was "Well done - it must have taken a lot of courage actually to say that, but we've always known, darling!" My dad was a bit upset at first - mainly because the family name wouldn't be carried on, but also because it probably is harder for the dad - but, as my mum said, they had both always known he was gay, ever since he was a little boy. They may have told themselves he was a gentle soul, or not very sporty, or whatever, but at the end of the day, they did know. It's just the actual telling that is difficult. Their attitude, once they had got over the initial shock, was that he is still and always will be their son and they will always love him. They are totally accepting of him now, and treat his partner as another son.
Whether or not you tell your parents is entirely up to you. Don't be pressurised one way or the other. You know your parents better than anyone else on this site. I know it's not a big issue for younger people these days, but it can be a shock if your parents are of an older or more conservative generation. Having said that, my parents are real died-in-the-wool practising Catholics, who you might expect to have been very anti-gay, but, as I say, they have been very supportive and accepting. Have you any brothers or sisters who you could tell first who would support you?
Whatever you decide, the main thing is that you accept yourself. Be happy and the very best of luck.