You can't, but then, you don't really have to.

Well, you can, start a new game using a new email address. It doesn't have to actually exists.

Most everything is reversible, and the pain not all that great. Especially early on. Demolishing a farm or house isn't all that big a deal. And you will probably do so more than once as you go along. e.g. Apparently the highest level barracks will take more than 1 day to train the max level of max troops - so you will ultimately only need the one barracks. Getting that far, however, you will likely want more than one - so you're going to be demolishing something. Probably in favor of houses or infirmaries. Then.

Most anything else, like studies, you're going to want eventually, anyways. Perhaps not in the order you now know you would have preferred, but you will soon catch up to the point where it no longer matters. Then exceed it.

i want to start over. when i began, i want city to be best. i thought that goal. am trying to catch up in everything since..can anyone help me,

You have to register and log in with a different e-mail address. (And start from scratch.)