Probably your first stop should be the diocesan vocations director - if you ask your parish priest he should be able to give you their details (incidentally, if you haven’t already done so, you should also talk to your parish priest about discernment). The vocations director will be able to recommend a suitable spiritual director. the vocations director will also be able to tell you about any regular discernment group meetings which take place (highly recommended) and any Come and See / enquiry weekends taking place at the seminary which your diocese sends its students to.
Finally, I also observe that your vocations director may well prefer you to wait until a year or two after finishing school. I know from my own experience that being told to wait is never easy to accept but at the same time it can also be very beneficial. You don’t necessarily have to go to college just as long as you do something (as opposed to sitting on the couch watching talk shows all day). You could work (like one of my classmates), travel, do voluntary work, etc.
