2nd Book: Believable or Unbelievable?

The second book I'm reading is called "Forever" and the author is Judy Blume. This book is really interesting but it has some parts were it seems believable or unbelievable, like in the part of the book when the character named Katherine said that she loves this character named Michael, I think that part is believable because mostly everyone loves somebody at some point. I also read an unbelievable sentence for example when Katherine is talking to her mother about Michael, her mother said that you cant go back to holding hands when your with someone. I think thats unbelievable because anyone can do whatever they want, and if you want to hold hands with someone again then you can as long as he/she is ok with it. Overall I think its a really good book.