That is perfect. At your age, it won’t take long to lose the weight doing the 20/4. That’s an excellent way to start fasting instead of just jumping in possibly setting yourself up for possible failure/disappointment.For some, 20/4 is hard enough.
Just keep your calories at a deficit.
Oh, and you may find yourself “accidentally” doing a 24 hour or longer fast one day when you don’t have the appetite or whatev at your eating window and you’re like “I’ll just not eat for 36 hours blah blah” and wa la… you’ve “accidentally” done your 1st extended fast