It is a bit young to be starting the menopause so I would suggest seeing your doctor - they can do a simple test to see where your hormone levels are and that will give you a better idea of what is happening. Heat in the vagina may be to do with an imbalance of the bacteria in that area. We have friendly bacteria there as well as in our gut and if the bacteria balance changes this can affect the delicate skin. Antibiotics are particularly good at messing up levels of friendly bacteria. I would suggest a probiotic supplement and Molkosan Vitality to restore better bacteria. Lowered levels of oestrogen may also cause this so a fermented soya supplement may help too.