IMO (an I've been on both sides of this, having started a small company in my 20's, and now as a hiring manager at a startup), "owner" is even more appropriate.
Even "Founder", to me, seems to imply a certain amount of effort was involved above and beyond the base paperwork.
If your company exists more on paper than in practice, skip the titles and just list yourself as Owner or "Self-Employed".
Many many many many people of all ages have managed to generate some cash flow from their determination and inventiveness. It's no great accomplishment, in the relative scheme of things, to have managed to generate a couple hundred thousand dollars in above the line revenue.
A Founder or CEO type title is, again IMO, appropriate when you have created something that has started to take on some life of its own, and might have a slim chance of continuance in your absence or departure. Or, when you have managed to convince some non-relative to give you a 7 figure investment.
I just dug out some old business cards from my little venture in the 90's. I just listed the company name, what we did, my name and contact info. The legal paperwork listed me as President or CEO, IIRC, but in the day-to-day operations I was just the guy that ran the joint. The company managed to do a few $MM in revenue, net me a bit o' cash and employ a couple of people besides myself.