Absolutely not do not make this decision prior to Quantico because you wont have any info
I disagree. You absolutely MUST make this decision before TBS, because once you get there, it's game over. Despite what your OSO told you about your air contract being non-binding to you, and despite the stated purpose of IFS, if you drop your air contract at TBS, you will almost certainly not be an infantry officer. You will probably be an adjutant, ground supply officer, or something along those lines, because Uncle has that new policy of "Oh, you don't want to fly? We won't make you fly, but that doesn't mean we're not gonna stick you with the green weiner by not letting you compete for MOS like everyone else."
That's EXACTLY what happened to everyone who tested Uncle's resolve on this matter when I went through TBS a year ago. One guy in particular stands out...he was a shit hot guy, physical animal, always on top of his game, at or near the top of his platoon, and voted the Gung Ho award winner in his platoon. Dropped his air contract to compete for 0302.
True to his word, Uncle didn't allow him to compete for MOS selection, and he got ground supply. What a misappropriation of human resources. It's stupid, but it is what it is.
I wanted to be--and was originally contracted to be--a pilot, but to make a long story short, was given some bad info by an OSO and ended up as an NFO, very much against my will. When I got to TBS and found out that I couldn't switch back to pilot, my first reaction was "Ok then, I want to drop my air contract and go ground." When they told me how hard they would screw me if I did, I decided that I'd at least sit on the NFO contract and think about it, which I did. After several months of being undecided (it seems like I'd change my mind every few days), I eventually decided that I'd rather ride bitch than fly a desk.
All of that said, and understanding that nobody can know better than you which community you will be happier in, I would say (based on what you've said so far) stick with the wing. Getting a FAC tour is not hard, from what I hear. I mean, people get "drafted" to do that job--from what I hear, if you volunteer instead of waiting to get voluntold, you can often get the particular FAC job or duty station you want. It won't be the same as being a rifle platoon commander, but it might be close enough. Definitely the best happy medium of satisfying your desire to be in both communities (I plan on either getting switched to pilot after my first tour as an NFO and making this a career, or doing a FAC tour on my way to the Civ Div). The reason I almost dropped it was a little different...I was pissed as hell and frustrated, and didn't think I could handle being 3 feet away from the only job I've ever wanted since I was in elementary school, and after mechanical engineering school (not because I liked it...just so I could be a test pilot, go figure), the last thing I wanted was 1.5 more years of school. I wanted to go ahead and get in the fight, kill some bad guys, then be able to get out and return to the real world a couple of years sooner. Now, I'm still pissed and frustrated about what happened, but I've come around to the point that I can enjoy the good things about NFO (and I love being a Marine and being an officer, and have never once regretted signing that dotted line...although I have no intention of staying active duty for a day past my commitment unless I get switched to pilot...although I kinda suspect I'll end up in the Reserves).
Oh, and TBS definitely turned a ton of people against going 0302 when I went through there...haha. I've seen it go from the very top to the very bottom of a dream sheet...hahahaha