Should i have surgery for varicocele if the sperm count is 5 mil/ml? i haven't tried to have kids yet. but did the spermiogram to check if fertility is affected by the varicocele. is it better for fertility to do it while younger (25 years old) ?

One sperm count in a young man is not enough to diagnose 'low sperm count'. You must have at least three several weeks apart with all the parameters of its quality included. For varicocele you need a scrotal Ultrasound. One you have that info. see a good Urologist to examine you and the tests to give you an opinion. People with low sperm counts are not sterile, they only have lower chances .

Your sperm count is low. You are not at all young to have varicocele surgery at your age. Varicocelectomy now or soon may well be worthwhile if left testicle is appreciably smaller than right, varicocele is very large and/or is symptomatic (Feels painful or heavy when standing, wlking or running)