表面的 should be okay I think, but I think you should use には. I would use the simpler よく内向的だと思われるが、実は恥ずかしがりやです。 Because superficially they both show the same signs..
Were you doing an exercise on interesting jikoshoukai, or did you actually do a speech of some sort, or start a new job? (If you feel that it is private information, feel free not to share, I am just very curious by nature! Sorry if I creeped you out haha.)
It was actually a class presentation. A short 自己紹介
I sort of procrastinated and wrote it last minute. It was just one line I wanted to add in about my personality but I couldn't figure out how to word it.