I would also suggest waiting - not so much from a fitness standpoint, but simply because you don't have a lot of time on the bike under your belt.

Being completely comfortable riding outside, among other people, etc. is going to be very important for an outdoor century ride. You may be in good enough shape to do the ride in three months, but will you be comfortable enough using your pedals, riding next to other riders, climbing, descending, etc.? My recollection is that the Santa Fe century has at least one quite notable climb. Will you have enough time practicing eating and drinking on the bike so that you are comfortable doing that? It's critical to be able to drink while riding.

So I'd suggest getting more time in riding outside, at least 5 months, before you do a century.

BUT - if you start riding now and you pick up these skills quickly, then you can probably do it. I just think that the bike handling is the critical component here that you may be lacking in such a short lead time.