Couples have struggles after when it came to dating after 3 months. You might need to establish what we are as a couple. Sometimes its about space if you two spend too much time together. I give mine space because before he had time to himself all the time and I respect that. Maybe the honeymoon phase is over and its time to get down to the gritty parts of the relationship, such as space, time and check ups from time to time.
I really agree with the opinion of @olderandwiser. At 13 teenage has just begun and you are really kids. Preferences and choices of people change at this time. Asker, you can talk it out with ur boyfriend if u want.