Sounds like a good story, anon. The picture is also good. As for not feeling skilled enough to start, (and I've never personally been there, so take this for what it is), I believe that starting is the hardest part, but also the most necessary. Many people improve their composition and details over time, especially in comics/graphic stories. Everyone, from Collins to Murata to Miura to Lee, started out with the idea. The execution was (and still is for everyone) a work-in-progress.
A word of advice though. The story is important to you, you mentioned. If it is also something you intend on publishing, please do not make the painstaking effort of making it "finalized" before taking it to a publisher. Draft it, have it properly written, but do not ink it. Have a few good pages inked to show that you can do it, but don't do the entire thing. It is extremely rare that something gets published its first go-around, and I'm sure there is an editor unknowingly awaiting for your manuscript's arrival, only to tell you that this, that, and the other thing need to be worked on a bit more.
Best of luck, anon. You are going to make it.