There isn’t really a ‘one size fits all’ answer to this question, as there can be many different factors on which individuals base their decision, which we should respect in each other, such as:
Personal goals - some people choose to be single longer, in order to focus on themselves and their life goals first.
Opportunity / Being Selective - some people may not find someone they are interested in dating until much later than when their friends start dating.
Family Values - some people have made a commitment to their parents that they will choose not to date until a particular age, or other readiness factors.
Past Experiences - some may have had negative experiences in the past that make them much more cautious moving forward, and in response they choose to hit the ‘reset’ button when it comes to dating, choosing to wait until they feel ready once again. Giving yourself space to heal, learn and grow following an unhealthy relationship allows for self-discovery that can be beneficial for future relationships.
With these things in mind, here are some things to consider, when trying to determine your own readiness:
What are my life goals right now? What do you want to accomplish during your high-school years? What do you want to see when you look back on your choices? Know that the choices you make regarding your relationships and sexual health will affect your life and your goals, either positively or negatively.
Do I know my own boundaries - what I want and don’t want, what I like and don’t like? Science proves that the feelings of physical attraction and acts of intimacy affect our brain chemistry, and therefore can be difficult to control. With this in mind, being ready to date should include knowing your boundaries in advance and being ready to communicate openly, honestly, and courageously what you like and don’t like, and what we want and do not want to happen in a relationship. If things get physical, the heat of the moment is a poor place to try and make those decisions.
What qualities am I attracted to and are important to me? Dating is partly about self-discovery - discovering what qualities you value and are attracted to in how a person behaves, and then using that as a guideline in your dating choices. You can and should determine some of this BEFORE you start attaching to a particular person. Take time to get to know if someone is worth dating! For example, most people value being respected (or we should). Is a person worth dating if they don’t consistently communicate in respectful ways? Listen and watch how people talk about and treat others, and take that as valuable information before you get attached. If a person is controlling of others, it’s safe to assume they will eventually do the same to you. If you think about what you want, it likely doesn’t include disrespect, control, manipulation, or pressure to do what you don’t want to do.
The Test of Time - Time can be your best friend when it comes to decision making. Relationships take time and effort, and only over time will a person be able to prove if they are trustworthy to be given the aspects of yourself that are most precious to you.