Is it permissible for a young man to secretly follow a girl, gather information about her, and invite her to wear the hijab without her knowledge, as a preliminary step to proposing to her in the future?

There is no harm in a young man conversing with a young woman if it does not lead to something forbidden, such as unrestrained gazing or speaking illicitly. However, it is better for someone who is not able to marry to turn his mind away from matters of marriage and to occupy himself with noble pursuits and learning the Shari'ah, and to fast frequently, based on the Prophet's (peace and blessings be upon him) saying: "O young people, whoever among you can afford to marry, let him do so, for it helps him lower his gaze and guard his modesty. And whoever is not able to do so, then he should fast, for it will be a shield for him."