Getting sufficient nutrients on a vegetarian diet is not difficult. It requires no particular thought unless you're doing a lot of exercise and need a huge amount of protein, but even then, it's pretty easy to get unless you want to avoid eggs, milk, soya, tempeh, nuts, mycoprotein, beans, lentils, protein supplements, etc.

Iron is more difficult in theory, but no other vegetarians I know have actually had a problem with it.