As a former runner, I think you can do it. I’ve seen plenty of fatties (we called muscular runners that, its a term of affection) run half marathons easily and I’ve known a few to run a full marathon. You’re lucky that you have so much time. I think the major obstacle for you is going to be that
a) you have so much time before it happens (people procrastinate the training)
b) You will be pounding your joints, mostly because it seems like you have never really run before. Take advantage of the amount of time you have and ease into it. Remember to do your stretching and foam rolling in the mornings and ice yourself after long runs.
c) The altitude/foreign country aspect. I generally wouldn’t advise to do your first marathon (an absurdly exhausting challenge) outside of your original country, and especially not at an altitude you aren’t used to. But hey, its your life.
I would recommend picking up an issue of Runners world (or checking out their website). They have a ton of programs meant to ease people into running, and usually each issue has a marathon training guide. The site may have some resources for bbers as well.
Hope that helps