Knowing where you stand with somebody can be really hard. For some people, as they get more mature it becomes easier, but for many people it is just as confusing when they are sixty as it was when they were sixteen! Remember that people are complex- and since relationships are between two people, they are twice as complex. Because no two people are the same, no two relationships can be the same- that means that comparing your relationship to the relationships around you isn’t always helpful, and can instead make you feel pressure to act in a certain way.
There is no “magic sign” that you are in a relationship with somebody. You can only know by communicating what you want and asking the other person what they want. When you want to be in a relationship with them and you think they might want to be in a relationship with you, ask them a question e.g. “Do you want to be my boyfriend?” “How do you feel about me?” “Do you feel ready to take the next step with me and be in a relationship?” You might feel scared about what they might say, but if not knowing how they feel is making you unhappy or anxious, it is better just to ask and find out.
Make sure that if they seem uncertain, or if they say they don’t want to be in a relationship with you, that you don’t put pressure on them to say yes. If they say “no”, try saying something like “Thank you for telling me how you feel. Do you mind if I ask you again (in a few days/next week/next month) to see if your feelings have changed?”
If it is the other way round and somebody is asking you, be sure you answer the way you really feel. If you’re sure you like them and want to be in a relationship with them, then brilliant! If you think you might be saying yes because you are lonely, flattered that they asked, or you don’t want to hurt their feelings, be a lot more careful. It’s okay to say no, or to ask them to give you some time to think about it if you’re not sure.
Different people move at different speeds in relationships. It is always nice when you are both “on the same page” and you can communicate that to each other, but quite often you will not be sure how they feel. The only way you can really know is by asking them.