My boyfriend and I have recently talked about starting to shower together. However, we're waiting to have sex until we know we're pretty serious about each other (this is something we both want). First, I want to ask if this is something you actually want to do or is it because you want to please him? You should never let a guy talk you into something you're not comfortable with. I think figuring that out is the first step to making that decision. Showering together can be whatever you two want it to be. It can be an intimate (yet still an innocent thing), it could be causal, or it could be a "it's business time". That's something you need to discuss with your boyfriend. You both need to be on the same page before you do anything. That way to avoid an awkward situation and enjoy yourselves.
I'm a virgin too, so I understand your hesitation. If you're a virgin due to religion, I would avoid it all together because foreplay, arousal, sex is all the same according to the church. If you're still a virgin just because you aren't ready or haven't met the right one, I would still be very hesitant. Especially since you obviously haven't talked to your man about HIS intentions. That tells me you guys aren't that comfortable with each other yet/haven't been together that long, if you guys haven't talked about this stuff yet. Unless it is very clear to both of you what the other wants/ is expecting and you agree on it, I wouldn't do it. Seeing each other naked, kissing, touching each other is very arousing and can easily get out of hand. And losing your virginity in a shower would be awful. If you're not ready to lose your virginity yet, I wouldn't open that door quite yet. Hope this helped, good luck to you.