Is gay sex advisable since i find it hard to find any girl?

Sexuality: First you should have sexual relations with a person you find attractive and interesting. If you have sexual feelings for men then this is a place to start; learning to be sexually intimate with one or more. If you do not have sexual feelings for men then you may find it beneficial to work this out with a therapist. But, homosexuality is a valid and common part of the human experience.

Your decision: This can only be answered by yourself, as sexual orientation and preferences to male or female is purely a personal decision. Sexuality is not detrmined if you can 'find' a girl, but more on your personal feelings of wether you prefer the same or opposite sex. If you truly like girls, than keep trying to find that right one, develop a relationship through trust and love, and sex may come later.