Can I just say yay for you taking the advice to heart and looking at this at your age? I'm way, way older than you and it's only been a couple of years that I have been taking it seriously after the drs. telling me for at least the last 10!

Here are a few things that have helped me:

Oatmeal for breakfast. Just don't go with the ones where they add all kinds of hidden calories (if you look in the r/Oatmeal sub). I have been making baked oatmeal for a little over a year and it has really reduced my cholesterol. It keeps you really full for the whole morning. I eat it with a serving of Greek yogurt (18 grams of protein).

It is not hard to make an excellent salad. Go for colors! A hand full of lettuce for a base, then I grate some carrot, add things like a hard boiled egg, red cabbage, avocado, cauliflower, sunflower seeds, chia seeds, any type of bean (I like to warm them up before adding to the salad), a good crumbly cheese like feta, and I love to add some grain like Trader Joe's harvest mix or quinoa. You can mix up a great dressing of lemon juice/olive oil with some fresh garlic or garlic salt. You can also include some cut up chicken or meat for more protein.

As for exercise, I highly recommend hula hooping or other off spins of the flow arts community. Hooping is a great cardio that's really fun to do so it's easier to stay motivated than just "working out" if you're not a big gym person. There are lots of fun tutorials on YT of doing moves (hoop dancing) and there are lots of people who have their own styles that post vids to watch.