Good to see your looking to get back into shape, all I can suggest is increasing the reps per set of each exercise every week. This way your exercises are going to get more intense every week. Also try different variations of pushups to work different muscle groups, ie; 10x knuckle, hands out, hands in, wide pushups. To make up the 40 pushups, rather than just 40 normal.

Same goes with the crunches, do a few crunches, then have your legs straight in the air and do crunches that way. The key is variation, makes your workouts more exciting and reduces adaptation by your muscles.

Good to see you've made a log mate, keep us updated