Well, if you have the time, you can take a shower and (get your hair wet), then let it air dry, and every now and again brush your hair with a flat brush. This helps me out :) And if you let your hair grow the weight will keep your hair straighter
This is just my opinion but I don't think you should feel any social pressure to straighten your hair! Your natural hair is very pretty and looks great on it's own! However, if you want to straighten your hair for a different look, doing it every once and a while shouldn't hurt it, as long as you're not constantly shoving it into a straightener. Using heat protecting spray should alleviate any worries you have. Good luck! :)
You can straighten your hair with a perm without using heat. I suggest going to a professional to do it. If the right perm is used to do this, your hair will be in better condition when you finished than when you started. I have had it done to mine many times and I have heavy highlights in mine. No frizz or breakage and lots of shine. This is not done on rods, its just combed thru. Good luck to you!