sexing the plant is onyl to determine of you have a male of female plant there. ive lost the link i had which helsp show the difference between males an females. but if you see fine hairs growing then you have a female! but if you see balls or nut sacks as some call them, then you have a male an see the scrape him unless you have a female growing with it an fance polinating it to get some free seeds.
but from a super quick google search i came up with this to help you identify your plants sex when it begins to show signs fo its sex.
http://www.growweedeasy.com/what-is-the-difference-between-a-male-and-female-marijuana-plant
p.s you will not be seeing tricomes at this stage of the plants life. tricomes are what you look for be hunting for during the later stages of your grow depending on the strain an grow setup tricomes might start appearing after week 6. as the tricomes are what most growers target to help them get the desired buzz. weather it be head high from milky tricomes or the amber/milky tricomes for that mixture of a head and body type effect. i hope anything here helps.