All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
First of all, we ask Allaah to reward you for being keen on learning the religious rulings, and help you perform good deeds and protect your religion.
With regard to your question, you did not mention the reality of the matter on which you made an oath not to do. It is confirmed that the Prophet said: "The oath is based on the intention for which it was given." [Muslim]. Therefore, if you did what your family wanted to prevent you from by making this oath, which is meeting this person as you mentioned, then you are obliged to expiate for breaking the oath, as explained in Fataawa 82135 and 82501.
On this occasion, we remind you that it is forbidden in Islam for a woman to establish any affectionate relationship with a marriageable man, as this is a means which could lead to Zina (fornication or adultery). Therefore, you are obliged to repent and not do the same thing again. For more benefit, please refer to Fatwa 81356.
Finally, we advise you to spend your life in the obedience of Allaah and keep company with pious women who would help you remain steadfast on the obedience of Allaah.
If this man is suitable for you as a husband, then he should ask your hand for marriage and approach your guardian for this purpose. It is confirmed that the Prophet said: "The best solution for those who love each other is to marry." [Ibn Maajah].
Then if he is determined to marry you, it is recommended that he sees you and you see him, and this is something legislated in religion.
Allaah knows best.