Let me see if I got this straight. You're now 47, and you started writing this first novel at 46, and completed it, and you're now worried about not having a follow-up?
I wrote a novel in my mid-late 20s, and a variety of stories, while getting an M.F.A. at the Iowa Writer's Workshop, and couldn't manage to get anything published. I then drifted into an unrelated career, and put fiction writing away for many years, resuming with a new and much better project at age 48, and had a couple of moments of what seemed like promising success (winning some money in contests, getting some requests from agents for full manuscript reads, etc.). And wrote more stories. And achieved exactly nothing in the way of publication. I become 62 tomorrow, and I'm still hacking at my way through a third novel, with no prospects or aspirations of success.
And you're worried?
caw