It is vital to remember, that you are on a journey. No journey is completed and 'over' in a flash, things take time to reach their peak and we adjust over time. There is no need to dive in and make everything difficult and unachievable from the outset. Small changes go a long way to creating the best version of yourself. Just prepare yourself and plan ahead. Think of it as making a pledge to yourself.
For example, weight loss doesn't have to mean starving yourself and cutting out everything you like from day one! (if you are the type of person that can do this successfully...great). It can, however, mean making an adjustment, by saying to yourself "I will replace half of my usual portion of pasta with vegetables, so I don't feel hungry."
When you go for your walk, say to yourself, "I will reduce the time or distance of my walk, but I will do a power walk." Any small, positive change, is better than no change at all.