A not spriter, spriting.

[vengefuldodo]

   

Hello all, I was wondering if stuff like this was allowed... technically it was made in a 3D modeling program, but converted into a sprite.

[-Ash-]

"But converted into a sprite" Uh, what?
A sprite is an image that has the purpose of being controlled, and is typically pixel art. Your image doesn't fit any of those points. Its just a rendering (a very poor one) in a strange pose, is large, and isn't a sprite. If we ignore that...
The texturing (if it even has any) is terrible. No actual idea of texture is applied, its just solid eye sore colors. The main model looks like a mix of classic mega man (possibly from the smash 4 models) and some sort of ZX or Zero series body? The proportion and style changing is jarring. Not to mention the googly eyes and line mouth. This just screams of laziness as a 3D model.

Avoid model merging. Actually texture it, and don't use solid colors if the model wasn't built with them in mind.(color theory is a skill needed in texturing.) Honestly i'd avoid doing modeling as a starting point, jump to drawing, painting or possibly pixelart.(personally I wouldn't recommend pixelart as it can make learning certain things much harder as it is a very meticulous medium that requires a lot more care to look good, drawing is probably the best option to learn everything from) It'd make things easier since you need to learn a lot of fundamentals before modeling will make any sense or even look good 90% of the time.