Hello My Age Is 19yrs And 7months. I Feel At

Hello my age is 19yrs and 7months. I feel at times that my penis is a bit small. Moreover i masturbate almost 2 times a day does that in anyway effect my health and size? AND another part of my question i have a girl friend shes 4 yrs elder to me she has not been into sex ever. It was only recently when we met she came to knew how to masturbate so is there any tips for it and does masturbation for girls during their periods helps to ease the pain..?