For your reference, my variation.
1) But at the same time, I started to go to an acting school, and my personality changed. When I was playing drama, I had to bring various myself out, and in this process, I could find the many sides of myself. Therefore, even after I became a grown-up, I feel as if I’m playing act for a little, when I’m talking with people. 「 若干」はなんですか。→a little, somewhat
2) What do you mean, “I’m playing act”?
3) I think after you took part in a big content, called "Love Live Sunshine", you became well known so fast.
4) Well, to tell the truth, I can’t feel it. But when I appeared on Anime Expo 2016 which was carried out in Los Angeles in July, I heard cheering voices "Kanako!" from the audience, and at that time I could consent, it was truly a big success. I was surprised that the people of the country, where I've been only once, were supporting me. It made me feel tense and determined at the thought of my job. 「なと」の最後はなんですか。→「~なんだな、と」It’s like that, I thought.
5) I couldn’t fall asleep, so I went for a little walk. The temperature was just right and night was pleasant. Maybe it was a last night, when I can go out without wearing a coat. Now, it seems like I'll be able to fall asleep. Good night. 「For 羽織らず, is this verb used for a specific clothing?」→ Not for specific clothing. But it is used for relatively light outerwear, like jacket, cardigan and so on.