The first year IS difficult, but mostly because it is such a steep learning curve for the teacher!
Also, you aren't in charge of your OWN classes, per se, and the students know it... next year you'll start out the year with the students and YOU will be the teacher they listen to
Students are ALL looking for the same thing, believe me! Respect them, while setting clear guidelines and expectations (ands this can be the hardest part of the learning curve!); above all, be FAIR. The hardest lesson for the teacher is almost always this: IT DOESN'T MATTER IF THEY 'LIKE' YOU. Not all of them will anyway
That's not to say a person who doesn't like children should teach, though!!
Teaching - it's one on one, but it is NOT personal!
Don't let the job take over your life. The hard work you put in, in the first year, will pay off for you later - but it is a job that can expand to fit the time you give it. Set YOURSELF deadlines, and STICK TO THEM [eg. I will NOT work after 8pm on any given night except in the most dire of emergencies!] I have seen too many student teachers burn out working through a fourteen or fifteen hour day (or longer!)
Enjoy it though - cling desperately to why you've made this change (I changed careers to teaching in my thirties, too!) and you'll be just fine. The hardest part of all might not be the students at all - watch out for the staffroom!! ;-)
Best wishes, and congratulations on your career change!