Good choice--enjoy! I'm an oldster, a late-bloomer, having returned to sax several years ago after a long absense. Had little experience with anything but concert band, but @ three years ago, my community band director decided we needed a spin-off big band, and as first alto in concert band and best reader I found myself thrust into the lead alto spot without a clue about what the role entailed. Well, I learned real fast and have had a ball doing it. I was already a good sight reader, but having to read lots of syncopation and take the lead while doing so was a real challange for me; the whole first year in that role I was constantly being admonished to "play out more". At this point, with a couple of years behind me and a set-up better suited to big band, I'm pretty comfortable in the spot and haven't had any serious challengers. I'll probably never be able to really improvise, but mercifully, our charts usually provide an alternative written out solo which I can and do play with ease.
Sorry to be wordy. This is by way of saying "kudos to you for being good enough to have the choice---you will learn a lot and be a better reader and player for the experience, all while having a great time!