Is mineral makeup really that good?

because when I try it, it always looks rubbish. I apply it little by little, don't use too much, but I have really greasy skin, so I have to apply it twice to start with, then it needs blotting after an hour, just like every other makeup I use, but when...

I blot it, it sort of pulls the makeup off a bit and leaves things that look like massive pores and as though I've really mucked up applying it.
Also, could you tell me how old you think I am, because all I get when I ask at boots about this makeup is oh you're too young that's why
xx

I think you look around 19. Sorry if im waaay off. Mineral makeup doesnt really do much for me either. But whatever makeup you have on in that pic, keep doing it that way because you look gorgeous.