Boarding a young boxer pup?

Is there any problem with boarding a 14 week old puppy for 5 days?  The kennel I chose has doggie daycare so she would be playing with other dogs indoors and outdoors during the day and in her kennel at night and of course all dogs have to have proof of vaccinations.  My concerns are:
1.  Will her vaccinations protect her?  She will have only had her 3rd round of shots by then (the 3rd round 5 days prior to boarding day).
2.  Is it safe for such a young puppy to be around a pack of mostly adult dogs all day?
3.  Will all the training that we have accomplished at home be fogotten when I pick her up?  She almost mastered all of Level 1 games and happily doing very well with her potty training.
Any thoughts or advice is greatly appreciated.