Any advice or personal stories would be very helpful.
Time, the longer the better.
Over a year ago I was being uke and while trying to avoid landing on some kids crowded around the mat, I landed wrong on my neck and shoulder. Entirely my fault. Within a few days I could not move my neck or right arm without pain. Coupled with ongoing injuries to my knees from an old work related injury, I decide to take some time off and heal. Went to the doctor, physical therapy and started taking Tai Chi at the local community center ( I am the youngest person there at age 54). I figure to take at least another year before I will consider starting Aikido. This is based on my previous experience with injuries and not taking the time to heal them completely (plus at age 54 you heal slower).
My advice is take lots of time to heal. The injuries you get at twenty-five, if not healed properly, will haunt you when you are in your fifties.