I am wondering a 37 years old to masturbate because their is times that i do but i was not sure if it is normal ?

Vast majority do so: While the percentage of men who masturbate and how frequent they do so is higher in younger men, recent research shows 80% of men in their 30's masturbate. The figure is probably higher as some people are embarrassed to admit it. See http://www.sexualityandu.ca/sexual-health/what_is_masturbation/statistics and http://www.pleated-jeans.com/2011/04/18/infographic-masturbation-facts-and-statistics/