I was self-taught and then went to university for CS. I think a blend like this was helpful because it keeps me grounded in practicality. I've often found that many that only learned coding through CS tend to not really like coding and are very academic. To me this means they are not good at getting stuff done.
Being self-taught is great because it demonstrates some major motivations. But it also means you could be doing things the wrong or inefficient way as they are some techniques taught in CS that are certainly useful.
So even if you are self-taught take the time to get at least some CS background. I think it will also help.