Is this a good calorie calculator to use?

It looks a bit high to me. I recommend doing a google search for TDEE and put your stats into about 5-6 then take the average. Thats what I did.

MFP's works well for me. Why don't you try that, log here, and see how it goes? You can manually adjust from there. We're all a little different, and that's true with any calculator you use. One major difference between this one and other ones is that this one assumes you will add in and eat your exercise calories. So it will give you a base of (for example) 2000 calories and, if you run 600 calories worth, MFP expects you to log that exercise and eat 2600 calories. Other calculators don't. You put an estimate of your activity level and eat that every day. It seems to me that people who have very regular schedules like the latter. Those of us who vary exercise a lot day to day (or are more conservative), like the MFP method. It's up to you.

BTW, one of my son's is almost your age, and uses a fitbit zip ($49), which syncs with his phone and adds his exercise calories into MFP. It works well to give him a good estimate.