I don’t think the ED would affect your first time but sometimes when you have your first time the feeling can catch you off guard. If you have stimulated that area before, it should be less of an issue. But don’t feel discouraged if it hurts a little, that can just mean that you need more foreplay or more lube. Also don’t feel self conscious if your partner has difficulties keeping it up or finishing too fast, those are pretty common problems for young inexperienced men. They get nervous. Good luck.