my neighbor has a pom we believe is in heat.Iv'e always fixed all my females as soon as they were of age.So i'm not sure what the signs are or how long they can be in heat.Please let me know if a swollen virgina is normal.

Yes, its normal - along with bleeding for about approx 10 days and then she will be fertile for up to 2 weeks afterwards, though some puppies have a shorter first season she will still be able to get pregnant. The bitch must be kept very safe , not let off the lead or taken out for walks. I always write on the calender the "first day" and keep them in purdah for at least 21 days.