For me it's also hard to say. I feel as though I was always attracted to the same sex in a sense. However I would say that I was around 14 that I self identified myself as gay. I never gave it any push back, as a kid I always was somewhat of an introvert and because of this I never really took into consideration what other people thought of me, or whether they approved of me when it came to how I felt about myself. Also most of my friends were girls and it was never uncomfortable coming out to them when I was in high school.
My family went to church as I was a child, but it was more out of tradition as opposed to much of a way of life. While I consider myself an agnostic, I do have respect for religion and those who identify themselves as religious. I find most people of faith to be kind unassuming people.
It wasn't until 19 that I came out to my parents, I never feared that they would stop loving me or supporting me, but I was still scared of the unknown. I'm actually not quite sure why I didn't tell them earlier, I guess it just never seemed to come up. Also, because my sexuality hadn't seemed like a big deal to me, I guess I didn't have that nagging inclination to have the conversation with my parents. Anyway, they had apparently known for quite some time before that because my dad sat me down and told me he knew and that I should just be open about it, and truthful with him. He was completely fine with it, and to this day it's never been a problem. He even made a joke that sometimes he had wished he had been the same because women are so difficult to deal with (he's been divorced twice), so I appreciated that he felt comfortable enough to joke about it.
It's been 5 years since then, today I'm still totally open about it. I'm not extremely vocal or in anyones face with my sexuality, except for maybe a couple of occasions where I felt as though it was necessary to stand up for myself. I work a somewhat professional job around a lot of people, and if anyone asks I'll tell them, but for the most part I'm sure they can tell.
I've always considered myself an individual, and my sexuality secondary to that. I also attribute my parents support and them never making a big deal about the fact I'm gay for the fact that I've never felt the reason to wear it on my sleeve, or feel uncomfortable about sexuality. I have plenty of gay friends, and straight friends now.
All in all, I'm very open about my sexuality, while at the same time I hardly think about it. If that makes sense.