I am a very honest person, why does everyone think I am a liar?

I am a 13 year old girl and honesty has always been my best trait. The last time I lied was when I was 6 and lied about stealing a lollipop from a candy jar! But now whenever I tell a story about something cool that happened to me, my friends just roll their eyes and say "yeah right". I told one of my friends that I heard a wolf howling when I was going camping(which is true). And she just said "It wasn't a wolf. It was a dog." But she wasn't even there and I was in the middle of the woods, there were no dogs around for miles. I also rode the intimidator 305 and greyed out on it. So I told a friend this and she didn't believe me. I said "Well, you haven't ridden it, so how can you say that I'm lying?" She said "Because you always lie and over exaggerate." It just made me want to cry because I NEVER LIE! How can she think that? Even my best friend ever is starting to doubt what I say. What the heck happened? What did I ever do to make everyone lose their trust in me and how can I get it back? I'm considering not ever telling stories about the stuff that happens to me anymore, because I know nobody will ever believe me.