I am 40 years old and I like to lift weights but I am unable to lift a lot of weight. Is it still worth it for me to continue?

I have been lifting weights for a long time. I hit my peak in strength when I was about 37. I was able to deadlift, squat, and bench press a decent amount of weight. Then I took some time off. Then I recently got back into it. The gains are coming very slowly or not at all. I am not really gaining strength, I am merely maintaining strength. My numbers in the bench press, deadlift, and squat are not improving. My age has caught up with me. I can still lift more weight than an untrained lifter, but my numbers are not impressive. As a 40 year old, it takes longer for my body to recover after workouts, too. Is it worth it for me to continue with strength training?