First time trouble??

We are both virgins but we think it's about time. I don't know is it because of lack of lubricant or what, he just can't get it in without hurting himself.. I think we both have sufficient knowledge about it but when it comes to practice, we just couldn't get it right:-/ We have tried multiple times in the dark but it's just so difficult to get it in! Should we turn on the light? Or buy some lubricant?? We have tried in different positions and now I'm really confused. Help!