Sounds creepy to me! The fact that she just recently started showing you physical affection at 15 is very weird. I stopped giving my parents physical affection once I became a teenager because it felt inappropriate to me at that age. The fact that you said that you are getting turned on by her advances is not normal. I'm sorry, but who could get turned on by their own mother?!?! If I were you, I'd stay away from her as much as possible. Spend time with your GF. If you want to experiment sexually, do it with her. (but be safe about it, use condoms, etc.) If you continue to have sexual thoughts about your mom then you need to seek help. I'm not sure what the age of consent laws are in India, but your mom is being a predator.