Hair loss and hair thinning. I do?

I'm male of 23 years,I take good diet as well as sleep,my mother has good and thick hair even at age of 55 but my father had gone bald at age of 40,I had fine as well as thick hair some years ago with a normal hairline,from 1 year I'm suffering from receding hairline,my hairline is receded about 1 finger's width,in that area hair are still alive but not growing as they used to be before,they look as vellus hair,as well as my hair all over scalp became more finer than before,I can't hold my hair to any direction,I never tried minoxidil or any other topical lotion,so doctor I wanna ask 1)is that pattern baldness?if yes then how can I diagnose? 2)miniaturised hair can be long?because my all hair became more finer. 3)what should I do?