Please I Need College Help?

So, I guess I did pretty mediocre in high school, and am probably going to have go to community college sigh..... So my question is if I do good my first two years of community college can I transfer to someplace better? Also, is it to late to improve? i'm a hs senior this year? I will be graduating early this year after being held back in first grade (I'm dyslexic). Are there some cles I can take that will look good on my college application? plz hlp thx!!!