According to your description (“a bump down there”) it is hard to identify the bump; even if it is a genital wart (Human papiloma virus (HPV)-infection), not all HPV-infections are sexually transmitted. HPV and gential warts can be also transmitted by contaminated clothes, things, toilet stalls and baths... or spread from another part of the body of the same person. You can freely tell your mum about your discovery and then you can both go to a dermatovenerologist or a gynecologist for your examination.