Buying A New Bike / I'm Fat

For about a year now my wife has wanted a bike.  I figured it was a passing fad.  A year later, she still wants one.  The kids are getting to the age they want to ride theirs and we have nowhere around the house to ride.  We do have a nice bike trail nearby.  Now I will be 40 next month and I haven't been on a bike in about 15 years.  In college I rode mountain bikes daily.  I got really into it.  I didn't have a car at school so it was my main mode of transportation.  Fast forward all these years and I am finally ready to take the plunge again.  The only problem is that I have put on a lot of weight.  Okay, I'm fat.  I try to keep active but I am fat.  I need to get off my fat butt and get more exercise.  Hopefully this will be the activity that does it for me.  I don't know how much I weigh but my scale doesn't go up that high.  So as 40 gets near, I am making a pledge to myself to start losing weight.  I have a five year old and a three year old and it finally hit me that if I don't do something soon, I might not be around to watch them grow up.  Wish me luck.