The trump flows freely within you, wear your red hat with pride.
But I'm not a democrat.  And unfortunately I'm quite a bit older than 14.  And my personal tax return is quite a few pages.  So let me help you out with something... there is quite a bit that can be gleaned from tax returns.
Does he actually make the charitable contributions that he professes to?  He's a big talker, we can all agree upon that I'm sure.  There is well-founded skepticism that trump often does not follow through with his promises of giving.  What if he doesn't, how would you feel about his character and follow-through on promises?  I know, you wouldn't care... but most outside of the 33% would care.
Who does he do business with?  Are their interests in line with American ideals?  Again, you probalby DGAF, but most outside of the 33% do.
Does he have significant debt to the russian parties... would that information be relevant to the public?   I know, you'd rather be russian than democrat.  Go watch Rocky IV.
Trump being worth less than he professes (highly likely btw) would only be the cherry on top.