All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If this young man is willing to marry you and you are satisfied with his religion and morals, accept marrying him and do not refuse him just because of what happened to you after Istikharah (the prayer for seeking Allah's guidance). The most preponderant opinion in our view is that the person who performs Istikharah goes on with the matter after the Istikharah and does not abandon it unless Allah turns it away from him. Mar'aat Al-Mafateeh Sharh Mishkaat Al-Masabeeh reads: “There is a difference of opinion in what to do after Istikharah. It was said: “He does whatever he wants and chooses whichever he likes, either action or abandonment, even if his heart is not satisfied with any of them, because what he does will be good and beneficial for him, as Allah the Almighty will only facilitate for him what is good. There is no indication in the hadeeth that Allah would place in the heart of the one who performs Istikharah a relief or an inclination towards something. Likewise, there is no mention in it that the person seeking guidance would see a dream or hear a sound or feel something. Rather, he may not find relief in himself even after repeating the Istikharah.” [End of quote]
You should know that establishing relations between young males and females - even if it is for the purpose of marriage - is a door to evil and a cause of mischief. It is necessary to beware of taking these relationships lightly and it is necessary to be careful to preserve the limits and morals of the Sharee'ah in this regard.
Allah knows best.