Terrible destrier build.  18/18 for destrier?  No, no no.  Go 21/15.  The 1 more riding skill isn't worth it. 
If you want 1h/shield and polearms, go 21/15, if you want only polearms, go 24/15 (at level 30).
  
You can thank me now.
Also, I never understood why the "default" crosswbow/2h build is 15/24, why wouldn't it be 24/15?