Cardio isn’t going to help get rid of cellulite. You need to work your legs HEAVILY and be eating enough to support muscle gain and bag the cardio. It won’t go away overnight, but once you start to really start doing heavy leg work and build up the muscle there, it will gradually make the appearance of cellulite disappear. Good luck from a fellow cellulite sufferer. Mine is now getting to the point where it’s barely noticeable at all.
Doing a lot of cardio eats into your muscle so I’d limit it to a couple HIIT sessions a week and lift heavily. But you should also keep in mind not to be ONLY doing leg work - you should still be focusing on your entire body. And be lifting heavily for your other body parts as well. You want to reduce your body fat overall.
As far as your diet, go to the sticky in the Nutrition section and calculate your calorie and macro needs. The sticky gives you all the information you’ll need. You need to be eating enough to support muscle growth. Given your stats, I’d say you’re pretty thin so I wouldn’t eat at a deficit since you don’t need to lose weight. Whether you want to go on a full bulk is entirely your call. You’ll see muscle gains faster but there will also be some fat gains along with that as well. Recomping(eating at maintenance) can be slower going than bulking. So it’s entirely your call
eating “healthy” means different things to different people. Obviously you want to fill your diet with lean protein and fruits and veggies because those things work to keep you fuller longer, but you can eat whatever foods you like as long as it fits your macros. It’s all in the sticky but typically it’s 1g to 1.5g of protein per pound of body weight, the rest filled with carbs and fat and how you want to divvy that up is up to you. I try to keep my macros around 33/33/33 or as close as I can get because that seems to be working best for me, but some people like to do more carbs, less fat, or vice versa. Be anal about keeping track of your calories, meaning weighing and measuring and logging everything you put in your mouth.