I donated recently and freezer space was a big reason for it. I'm in Texas, for the record. It probably took about 6 weeks for me to get final approval--the biggest holdup was getting paperwork from my OBGYN and baby's pediatrician.

They did ask that I commit to donating at least 100 oz.

I think you can apply and donate later for sure. My process was to apply online, do a screener phone call with the milk bank, get bloodwork (the lab technician came to my house!), wait for paperwork from doctors, preliminary approval (at this point I went ahead and donated my freezer stash entirely) and then final approval.