Because adolescence is a developmental heroic journey, it is a given that you will be very different at the beginning of the journey than you will be as it progresses. That is true for romantic relationships. There is a general difference between romantic relationships in the early teens and the later teens. This doesn’t hold true for everyone, but it does in general.
Attractiveness is the major factor, particularly for boys. Having fun, having someone to go places with, status and fitting in tend to be central to dating. Romantic relationships might not be long-lasting even when they are intense. Girls more mature and different needs and desires than boys.
From 10-14 years, teenagers often want to spend more time in mixed gender groups, which might eventually end up in a romantic relationship. Younger teenage romantic relations may be more stressful and less supportive (provide fewer benefits), simply because everything is so new
Inner qualities become more important, even for boys. Closeness, sharing, confiding, having each other’s back emerge as key in romantic relationships – for young men and young women. Longer term commitments also become a greater factor in these relationships. Lots of skills in early development – emotional intelligence, communications, assertiveness, etc.
From 15-19 years, romantic relationships can become central to social life. In later adolescence there can be a shift from parents to romantic partner in who is central (time spent, support, confiding…)