Old grape vines in my Virginia backyard

Hello all, I am new to the community and wanted to post this here. I know very little about wine, grapes, or viticulture, but I have been doing some heavy research and am much more interested now in learning more. I moved to this property not long ago and found several grape vines in the backyard (four to be exact, all growing out of the same spot) and wanted to ask if anyone knowledgeable in this matter might know the possible age, rarity and quality of the vines, as well as if this is anything special, or just something run of the mill.

My location is in Northern Virginia, just east of the Shenandoah Valley. Posted here is a couple pictures of the vines, leaves and grapes. These vines have spread all about the yard, and have not been taken care of in what appears to be many years. The four of them have assaulted the trees, and have gone so far in multiple directions, my eyes cannot even follow them the whole distance. There are a couple posts and trellises back there so at one time the former owner was tending to them, but now it is in complete disrepair.

I am wondering especially if from the leaves, grapes and vines I posted here if it can be identified what exactly I have here. These seem to be thriving even in the unkept conditions, reaching up to the sky to get sunlight and even now in May there is an abundance of them. I am also really wondering if anyone here might be able to tell by the trunk width, just how old these vines are. I'd really like to put this matter to rest - even if it happens to be nothing special.

Thanks and I look forward to any information from the experts here!

In my opinion there is no good way to tell what these are. I suspect two different varieties based on the leaf shape. The first and third photos have one type of leaf and the third a totally different shape. I think your best bet to tell if they are something you want is to let them flower, set their fruit and later ripen. That will at least let you know if they are worth keeping. No way of telling their age by the trunks other than they are a number of years old and extremely unkept.