Hey Charlie!
Me and you are pretty much the same age, I'm 15, turning 16 this year. Although I am fairly new to astronomy myself, perhaps I can help a little bit too.
I myself have a 10" Dob (which I have only recently purchased). I know its silly (and dangerous) of me, but whenever I carry my scope around, I never take the OTA from the Base. Its pretty darn heavy and awkard, but I can manage. If you're a similar build (I'm fairly average) you should be able to manage a similar scope, even if you take the OTA from the base, thereby halving the weight. I think the problem for me isn't so much weight, but akwardness.
As for Astrophotography, one day I would really like to get into, as it fascinates me. So naturally, I currently take some pictures with my dob. Although due to the fact that when objects are being filmed (I use a video camera, and stack it in Registax) they move quickly out of the field of view (you can get about 30secs of video time with a relative zoom on Saturn of Jupiter) the images I have turned out are far better then I ever thought I would be able to get. Plus, word about has been that it is possible to buy a Goto or tracking system for a dob (And I'm not talking about the DSCs), thought they cost around the same cost as the scope itself. Here's my maths- the LX200GPS is about $5200 right? Well, a Bintel or Andrews 10" Dob are around $800? If you pay about $800 for the Dob, and about $800 again for the tracking system, thats only $1600, compared to $5200. Though, I probably got some of the prices wrong, anyone wanna check me?