its good if its your first,
you just need to add detail to it.
some tips how to make good decals
1:make it look like a t-shirt or maybea a collar shirt watever kind of shirt type you want
2:add some more detail maybea a collar or a shirt pocket? or buttons
3:make sure its transparent
4:post in gallery, get others opinion on your design,
if most people like it (not including noobs) release it but if most people dont like it,
dont release it and change the design flaws that you think it has(or if everbody tells you what the flaws are change the flaws)
5: if you got mostly good reviews from the decal after you released it (if you did)
upload it to rtb