Ironman training shouldn't be done in a straight line from couch to Iron Distance. Phased training allows you to build fitness by adding miles, but also incorporate rest so your body can absorb  that fitness & reduce injury risk.

regardless of that your plan says, if you feel tired, hurt, injured, or burnt out - take a day off (or two!). In a year long training cycle, those few days won't hurt your fitness one bit (they might even save it).

You're going to be burning 4,000-6,000 calories per day when training! You not only need to refuel your body, but do so with quality whole foods. Ice cream here and there is fine 😜 but whole (organic if you can) foods will serve the body well.

You're going to miss out on happy hours, plans, brunches, and other things. But if you want to become an Ironman, you'll have to get used to telling people "no, sorry, I have to train". It'll all be worth it.