I answered "since birth" since my hair has never been 100% straight. It's hard to say for certain what my hair's texture was while growing up because of all the hairbrushing. I have fine hair that goes straight when brushed out. I remember my mom combing my hair out and blowing it dry so it would, "stay that way," which would seem odd to have to do if it was straight, you know? Why was my hair so contrary? It got curlier as I hit puberty but I don't think it was ever really straight.
3a/b, fine, lots of it