Have been played it for alomost 2 years,can not get level up?

[snake811016]

I am level 10,most of time meet with level 12-15,is that the reason? I try so hard to aim...

[SONOMAMASHINE]

usually you level up quickly vs higher lvl's opponents, your performance must be bad thats why you didn't lvl up.

[Derrik ∞ GHz]

I am level 10,most of time meet with level 12-15,is that the reason? I try so hard to aim...

You just need to do better, unfortunately. It's a hard game.