Actually I fell in love with a girl and that girl also loves me but we don't really want to get into a haram relationship and maintain the rules of Allah (SWT). We want to be patient and wait till we can get married. The problem is that we're still teenagers and forbidden by law that we can't marry. In this situation, how can I still be connected with her? Can we chat sometimes on the internet having her sister watching her chat as a guardian? We're living far away from each other so there's not even a way to meet physically or anything.

1- You can speak to her occasionally if everything you say is appropriate and professional (nothing haram is said).

2- However, if you cannot get married any time soon (and it would years away before you would get married), then I don’t recommend staying in touch with her because usually staying in touch with her ends up taking an emotional toll on you both. You will get more attached to each other and it would be painful to be away from each other. Also, sometimes this leads to frustration and it happens with some teenagers that after a while (like more than a year or 2 years) they start losing interest in each other and even hate each other.