Time limit to start teaching after PGCE completion?

Greetings, fellow teachers! To cut a very long story short, I finished my PGCE four years ago but have never actually taught yet, as due to some health issues I could only work from home for a while. Now I am much better and could in theory start teaching. However, I have grown to rather enjoy my current job and don't want to quit it just yet. But I do worry that it's been so long already (four years, where did the time go!) that I might struggle to find a permanent teaching post the longer I leave it. At the same time I don't want to rush things and 'brute force' myself into teaching this very moment just because I am afraid my time is running out. I want the moment to feel right and I want to pick the right school for me. My question is, is there any time limit to start teaching after the PGCE? How much harder would it be to find a permanent teaching job 5, 10 years down the line from one's PGCE? Don't want to quite give it 10 years, but s**t happens! I trained in a shortage subject if that is of any significance.