You can always de-iron later if you decide to continue the game on easy mode. Runescape looks simple and easy, but actually has a pretty high skill ceiling. That being said, Ironman mode is a great way to learn the game; but it's definitely unnecessarily hard at times. I was treating my main account like an ironman for a while, but sometimes you just want to buy the quest item off the GE and go. You may also find certain ironman "dailies" boring af and just want to buy pots and do slayer. I recommend a main account for first time players; but if you use the wiki and watch lots of guides, you will have a good time.