I didn't plan on "coming out" to my parents so early either, but I had to
I was 19 and had been with my first girlfriend for about 5 months already (I'd finally admitted to myself and my friends I was gay when I was 16). Anyway, my gf was living in London at the time we got together but was soon going back to Uni on the Southern Coast and said I was welcome to stay anytime, which I of course was happy to take her up on
Which left the situation of telling the truth or lying to my parents. The be-all and end-all is that lying to my parents would've hurt them a lot more than me coming out to them.
I'm 25 now and they are fine with it. Am With somebody totally different now and getting married in 2 years, wahey!