Re: should I save my first marathon for a "big" one?
I have been a straggler in a small local 25k but it's on one of my favorite running routes--a measured bike path in Fairmount Park--and I love it whatever place I come in... there are always people I know and it's a friendly kind of race. When I have run the Philly Marathon, I have to admit I prefer the parts of it that go through Fairmount Park even tho crowd support isn't as much there as in the city. But I'm not a crowd person, so YMMV.
I've enjoyed the big events--NYCM, Boston--but the small ones have a flavor all their own. Even finishing at the back in a small event, if it's the right kind of small event, you'll have people hanging out waiting for everyone to come in and cheering for you.
Plus, sometimes you can win an award in smaller races even if you don't turn in a fast time. In the 25k, maybe just b/c I'm in the women's 50s age group and this is a sparsely populated group in this race, I find myself still getting awards, despite my time. I'd run this race, award or no, b/c I have a lot of medals and such, but still it's kinda fun to hear one's name called for an award, especially when you win one for the first time.
Also, you might want to consider ORBrewDad's advice if you're fairly new to the game. If you're feeling pretty good and comfortable w/ your long runs, not getting injured, maybe it's fine, and you can go for it, but also be aware of the stress on your body and be flexible in your planning. There's no need to hurry into a marathon. As you're seeing in the various posts, there are lots of choices.
Whatever you decide, good luck in your training and racing!