Maybe you are looking at it the wrong way. Most people don't just go out and confess to people. At least in my experience, most people I see, one person invites the other on a date and many times will go on a few more and some of those times, they will continue dating. Look, all I'm saying is that you should pick one (
>>3 is some pretty good advice) and ask her out on a date. If she flat out says no or things go badly, give it a while. Then you can maybe try again.
Lastly, stop thinking that you are in a bad situation. I don't think anyone here is telling you it is wrong to crush on more than one girl. Doubletiming, now that would be a problem. Just crushing? Way more normal than you think.