But why? No one knows the future of bitcoin, even your friend doesn't know it. It was your own decisions anyway, don't let others dictate you it was your own money so it was in your control. But if you feel your friend was right and have a basis base upon on his statement then sell it. Just tell him that you want to see what is the result of your investments in the future tell him you don't care if you lose or gain it was your own decision because it was your money.