Disc dehydration is a very early phenomenon of age related changes that happen in the spine of every human being after certain age. MRI is dependent on water conten of tissues and that is why they report it on MRI. You should not be too much worried about it. No one can stop or reverse ageing. !. What you need to do is to have a good exercise routine including spinal muscle strengthening exercises.. and maintain proper posture while sitting or working. Physiotherapist can help you in this regard. Do not get scared by reading a lot of material on internet. See a qualified spine surgeon for proper evaluation and guidance if you have any significant symptoms. Take care.