hiya sorry i havnt been on since this morning.
seen as your male and female could have already mated , i think maybe a vet check up is in order , they will do a health check and be able to tell you weather or not she is pregnant.
seen as you are not a registered breeder i will urge you to let this be the only litter. no point in me telling you not to do this and not to do that as you didnt come here for a leture lol.
but please do get them both spayed and neutered and like TNR! said if you cannot get the kittens S/N then please do follow ups to make sure there new owners will.
if for some reason you cant get to a vet, then maybe go along with the idea she may be pregnant , better to be safe then sorry. start her on a high qulity kitten food , wet and dry kind. set up a few birthing boxs and nearer the time you think she may be due maybe set her up in her own room with a litter tray , water and food ( make sure you dont use the clumping litter as when the kittens start to get around they will eat litter and this kind is not good for there stomachs.
feel free to PM me if you have any other questions or if you would just like a chat.