I'm 13, and a bit out of shape. Any tips for starting Parkour?

I've been interested in Parkour for a month or two now, and really want to try it out. I've messed around, but have never done anything really considered Parkour yet. I am 13 years old, stand five feet and three inches, and weigh around one hundred and thirty pounds. I know I am a bit out of shape, and I'm hoping Parkour will motivate me a bit and actually get me into shape. I'm not very strong, but I'm not horrendously week. I have okay shoes, lots of time on my hands, but I lack motivation, etc. I feel like I'm kinda fat, and I don't mind, because I want to do something about it. I just hate that I'm not great at sports, and I get winded easily. Any tips for starting out and maybe ways to get motivated or some basic work outs I can do?