I found myself in a similar situation two years ago. I bought a light aircraft and realised that I had not held an SEP Rating for 22 years. I came to the conclusion that I had forgotten a hell of a lot about little aeroplanes during that period.
I joined a local flying club and flew 5 flights (totalling 3 hrs 50 mins) before I felt back up to speed and then flew a renewal flight with an examiner (1 hour) which went very well.
I am very glad that I did it. There is a long list of experienced professional pilots like me who have ended up as statistics when going back to little aeroplanes.