I hope to share my passion of flying with students. Ok, sometimes it will be hard because everybody is different, but it will be a challenge for me.
That is a great admirable reason to want to be a flying instructor and I hope that will still be valid after a year or two in the profession. Quite a few start out with similar sentiments but sadly after the repetition and sometimes long days get disheartened after a time. Flying instruction is hard work when it is done properly, I always wondered why school teachers had long holidays till I started instruction (at around your age).I once heard a Monarch captain describe instructing as the labouring of flying (I prefer to call it hard work when you put everything into it.).
Part of the problem can be the school you work at. Four one hour flying details per day with briefings etc is enough for any instructor in my opinion but many will want you to fly more and when you get back from one flight your no sooner in the door and they expect you to be back out in the aircraft, generally that sort of school can be challenging for both instructors and students so pick your school/club carefully is my advice.
Also part of the problem also lies in the title of your post--about flying the aircraft. Being a flying instructor is not just about flying, it is about being able to brief and lecture, being able to prepare students for exams, being able to sell PPL courses, being able to supervise other pilots, some who will have more experience than yourself. You need to be able to pass on a lot more than enthusiasm. One poster said you remember your first first solo, sadly I do not but what i do remember is that no student of mine has never been involved in any sort of incident ever and I find that much more rewarding.
Good luck