Basically -- yes, you can certainly start the "start a PTO" steps now. You can actually do those steps anytime.
Seems the crux of your question is "what's the status of our PTA?"
If you were calling yourself a PTA last year and had a membership drive, then not paying dues (and presumably not doing/using any of the PTA "stuff") likely makes you suspended or not in good standing or some such.
If you want to just start a PTO now for the new school year and formalize the end of the PTA, you can do that. I'd make sure you spend that PTA account down to zero and start an entirely separate PTO account. Those old dollars are really the only thing anyone could ever lay claim to (and even that claim is circumspect, at best). After that, just don't have a PTA membership drive and don't have any PTA meetings or the like. There'll be no members, no meetings, no money and... basically... no PTA. Simple enough.
I am a new co-president of a PTA. However, it has just come to my attention that the board did not pay the PTA dues last year. Sure enough, a search for PTAs near me done on the PTA website yields no results. Supposedly, the PTA hasn't questioned or contacted our group.
SO. Can we simply start the steps to become a PTO, now? What sorts of things might we have to 'worry' about AFA the PTA goes?
I'm still perusing the boards and soaking this all in, so, my apologies if my question seems naive.