L1/2, 2/3 and 3/4 sinal canal diameters is around 8mm on MRI report. This is relative stenosis.
Although no one can predict so as to when eventually you will loose bowel/bladder sensations, this depends on your lifestyle and modifications.
If you have low back pain with radicular symptoms then you can choose surgical decompression over conservative as you are just 34.
Next Steps
Consult online for conservative trial. To see if works or not.
Health Tips
Spinal canal diameter 7mm or less is a surgical emergency. more prone for paralysis.
You are just there (8mm) where as normal is around 15-17mm.
So choose wisely.