You have 30 days from first photo is taken to "claim them" online. Once you claim them you have 30 days to edit and order prints/CDs/etc. Your time frame will be fine.
If you also find yourself needing a few more days they have the option for a price to extend the time. I did that over our Halloween and Christmas trip. I waited as long as i could to activate the photopass then had 30 days from there did a 15 day extension to get me to December and was able to put both trips on the same disk. Also we bought the Photopass disk stock pictures that had the free photopass disk included.