If i'm 24 and want to start having kids at 30, what should i do health-wise to prepare?

Fantastic question!: You certainly have plenty of time to achieve or maintain your ideal weight, eat a 'clean' diet, discontinue habits such as smoking or excess drinking, and take a good multivitamin daily. It would also be a great idea to do some traveling or engage in other experiences before your pregnancy, as these things will become more difficult when you start a family. Best wishes!