How big is this hoop? Usually the biggest hoop you want is a max of 18 inches or so across. Larger than that, and it becomes difficult to reach. Ideal size is usually in the 12 to 14-inch range.
Is it a round hoop or an oval hoop? If it's oval, it was designed for hand embroidery and may not provide the best tensioning for a quilt. Quilting hoops are round or (in the case of Grace hoops) squarish.
Is it a floor stand hoop? Lap hoop? Or one that requires you to juggle the hoop as you stitch? The latter requires more expertise.
Especially with an old hoop, I would want to experiment hooping a muslin quilt sandwich in it to make sure that no discoloration transfers from the wood to the quilt.
Have you ever used a hoop before? It does require practice to get comfortable. A common newbie mistake is to make the quilt drum tight in the hoop when actually a lot of slack in the middle is required to allow manipulation of the sandwich onto and off of the needle. Also, it's a good idea to remove the hoop, or at least loosen it substantially, in-between quilting sessions so the fabric does not get stretched out of shape.
Can you hand quilt another, smaller quilt first to make sure this is going to work for you?