So take your time. Do not let the pressures of society or the heat of the moment push either of you before you are ready. For every time you don't go all the way, you leave a space to grow more united in your relationship. And if you feel apprehensive that's okay. Men are not the pillars of concrete that they claim to be.
Men also react on emotion and impulse.
Both are necessary in sex. If your apprehension is telling you something, you should listen to it. You and your partner need to be in open communication and agreement about the issue and your growing desires. You need to prepare yourselves for the moment when time stands still, when your hearts furiously pound, and when oneness is absolutely compelling. By If there is no struggle, there is no progress.