How can I ask my friend out?

Hi. I have been a friend with this one girl for a long time. I have never asked a girl out in my life, nor have a been on a date in my life. This one girl lives in CT, and I live in MA. We have known eachother for about 6 years. (her and her brother have a summer house here and they come down for a coupla weeks in the summer) and just the past couple of years, I have started to have feelings for her. She really used to be a friend, and now, I am seeing everything 'come out' and I have true feelings for her. And I think she might have feelings for me too...and I am not entirely sure how to handle this situation because she has been my friend for a long time. I do have a confidence problem. And I always think that I would rather have her as a friend than not have her at all...and because she has been a friend for a long time, I dont want the friendship to get messed up if it doesnt work out. But then again, I always think that she likes me too...I just have this feeling...
Can someone please give me some advice? =) thank you.
-Ryan

wow this is a tricky one. from what you have said I think this girl likes you so I think you have no problem with gettin together, but as you said you dont want to mess up the friendship if it dosnt work out. but the friendship will only get messed up if you break up for a reall why bad reason I.e cheating. and I doubt you would do that from what I have herd you say. so I reakon you should do something about your feelings for this girl. now if you are to shy to ask her out when she comes down for the summer and you guys are hanging out I think you should lean in and kiss her and see how she reacts im sure she would love that then if it all goes well you should ask her out and forget your confidence problem you have known this girl for along time so dont worry! just be yourself and yeah good luck with every thing I hope this helped you