Don't worry that is completely normal and almost every women gets a yeast infection at least once in their lives!
1. Vaginal yeast infections occur when new yeast is introduced into the vaginal area, or when there is an increase in the quantity of yeast already present in the vagina relative to the quantity of normal bacteria. For example, when the normal, protective bacteria are destroyed by antibiotics (taken to treat a urinary tract, respiratory, or other types of infection) or by unsuppressed drugs, the yeast can multiply, invade tissues, and cause irritation of the lining of the vagina. Vaginal yeast infections can also occur as a result of injury to the inner vagina, such as after chemotherapy. Also, women with suppressed immune systems develop vaginal yeast infections more frequently than women with normal immunity. Other conditions that may cause women to developing vaginal yeast infections include diabetes, pregnancy, and taking oral contraceptives. The use of douches or perfumed vaginal hygiene sprays may also increase a woman's risk of developing a vaginal yeast infection.
2. You should really see a doctor so they can prescribe you a cream that can help get rid of that or you could try some over the counter cream but that takes longer to cure the infection, rather than a prescribed cream.
3. Ask your mom if she's ever had a yeast infection. If she has she will know the symptoms and what you should do about it. More likely than not she has had a yeast infection at least once.
4. Try applying a cool washcloth over the vagina while sitting on the toilet, using a light fan directed at the vagina while lying down, applying a chilled ice pack to the vagina, and switching to mild soaps can avoid further irritation. Try not to scratch because that can cause vaginal tears in the vaginal skin which can cause further problems and scratching doesn't really help anyway.
Hope I've helped and just tell your mom so that you can get to a doc to get rid of the infection faster. I had one while I was pregnant and the doctor prescribed me pills that got rid of the infection in 4 days to make matters worse I had a urinary tract infection at the same time as the yeast infection!