Hey, don't think much over that !!
Electronic charge is just taken as -ve , it may as well be taken positive ( don't take it on exams , as they will take ur marks as -ve !! ).
Instad note an interesting fact . See in classical electrodynamics we always have the quantity '' q v '' together , as a product form .
Now supose u take charge of electron to be positive then electron flow will be taken in the opposite direction ( i.e. along the current ) then laws of physics remain the same .
It is unfortunate that electronic charge was assigned -ve and its reason was that when electricity was discovered first , people simply characterized two types of charges as + ve & -ve arbitrarily .