Hello, I think I can help you answer this question.

In my opinion, there is no fixed time to have a boyfriend or girlfriend. True love can happen anytime. But you have to think clearly before you have a relationship with the boy or girl you love. Are you willing to take on this responsibility, and is your current ability enough to support you to bear this relationship?

For example, if you are just a student, you should consider whether you have enough time and money to support and maintain this relationship. Will such a relationship affect your work and life at this stage?

What I want to tell you is that love is the spice of life, and it is two people who work together to make life better.

But if you feel that this moment, this relationship is not suitable for it to happen. What I mean is that he will become a burden to your life and will not make you happy, so don't establish this relationship.

Of course, these should be your own ideas, when you think about all this, you are fully prepared to take on this responsibility. If you decide to go on with each other.Then this is the best and most appropriate time.

Finally, I wish you a natural love and meet the right person at the right time.

Never go to the supermarket when you are hungry, and never fall in love when you are empty.

If you think that is a right time, it's the best age. 
My English is poor, so I explain it in short.
Love is not the whole life, and it's not the only way which must be passed. There are many interesting things in your life. If your are not meet your true love, you just improve your ability and try your best to be better. Maybe on that way, you could meet him or her. It's so cool when you know each other, you are in the best state. If you never meet true love, you could enjoy your own fantastic life!

Love yourself before you love others.

I think you can have one everytime. However, you must take your respection. You should know what you are doing, how you will do in the future. Nothing's relationship is easy, and it's multiplying. You should you take it in part as who. I think you shouldn't regret that you are doing.

When you really understand how to love yourself.

I'm going to take the senior high school entrance examination, but I'm very anxious. What can I do to help me?

I think this option is no the best answer .because love is not like a choose or a test, so we don't know what time to meet our own love. Love is not a decided, it is some feeling and sense. So if you know how to love yourself first. You can accept love who can protect yourself and knowing how to love. This is a crazy world. If we met, why not try? You should remember everytime is the best time to love you!

When the time is right, you feel it coming. (even if it'll end up not that well, you can get sth. from what you've lost.