Frankly he shouldn't have said you could, especially with a female that young! He should also have suggested some kind of quarantine, bunging a new animal in without any health checks or faecal samples could mean that you've introduced a nasty to your male (or to the female).
You can potentially house them together but I would wait until the female has fully matured (around 2 years old) however it's best to keep them separate permanently due to dominance and mating. They will breed and they will need to be separated anyway for the female to lay and recuperate in peace. Sometimes housing together works out, sometimes it doesn't - always err on the side of caution though!