Dusted off the mountain bike this week

Started riding my mountain bike for the first time this year.  My butt is sore and has to get used to the seat again.  My bike is a 2001 Brodie Fury.  The frame was made in Canada and the shock made in Italy.  Good quality stuff.  I think these bikes are made offshore now.  The rest of the components were replaced over the years.  This was my first good bike.  I bought bikes from Can. Tire and Walmart in the past but as I became more serious with mountain biking the cheaper quality bikes only lasted about 6 months.  The first year I put 5000km on it and the second year another 5000km.  It was exciting to see my CatEye bike computer turn 10,000km.  Well now the monitor broke and I lost track of how many kms I put on the Brodie.
I don't ride as much as I used to.  I'm getting old and I can feel it in my joints.  I think I put on the beef this winter.  I'm starting off on a slow 10km.  I hope to work up to my 20km route with lots of hills and in under 1 hour.  Dream on.......