Changing my life now so that I can age well! 50 is on the horizon!

Congrats on your commitment! I was in the same place about 5 years ago – I was in my early 40s and starting to get out of shape, I rejected that I had to accept the decline of my health associated with aging, and fitness became my midlife crisis. I started logging my diet consistently on MFP, and after a month, I was able to start cutting down on certain foods and replacing it with foods that were better aligned with my fitness goals. (For example, I stopped robotically drinking milk and OJ every morning because I was getting more than enough vitamin C, D, calcium, etc. from my general diet, so I replaced a few hundred liquid calories with calories from solid food that kept me satiated longer.)

My best advice is to get a handle on how many calories you should be eating and the correct mix of macros (fat/carbs/protein) and just consistently eat within those parameters. Spend a few hours a week doing strength training and cardio (especially strength training, if you want to have a nice body composition, strong muscles, good bone density, etc.. As you reach your 50s and beyond, strength training will make you more resilient and able to absorb some of the negative things that happen to us as we get older (broken bones and torn muscles from falls, for example)). Build sustainable eating and exercise habits that you can see yourself doing for years. Best of luck!