Starting p90x3 and counting calories

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Today was day one of my new fitness journey! I started to track my calories last week to get used to it but today is my commitment day. I also started my p90x3 doing the Total Synergistics video. My HR monitor said I burned 253 calories during those 30 minutes! I am 34, 5'2 and weigh 155lbs. I am hoping to be at my ideal weight(body shape) by my 35th birthday next April. I have had ups and downs before but I am hoping for a mental lifestyle change this time so my results will last. I am excited to be starting the p90x3 and tracking calories. Has anyone had experience with this? I am also looking at a meal replacement- Ideal shape.