Do you have a photo? A 13mm pearl is quite large especially if it's round. Is the shank large enough to keep the ring well balanced so it doesen't spin on the finger?
Might be a bit large unless you're going for a statement piece. You have to measure the width of your finger. I have about 15mm across. With 13mm pearl the setting would probably cover adjacent fingers.
I wear it and love it, but it's not 11 mm tall, either. I also have a very tall ring, about 10mm tall and it bothers me, I don't wear it a lot. I'm afraid I'm going to knock it into something. Pearls are pretty sturdy, but if it's AAA, I'd hate to accidentally make it a AA. If it's a AA, with a few small blemishes, it might not bother you too much.
I think you need to try it on, to get a real idea. If it's on the net, check the return policy carefully, it may be worth a look.
Here is a high end ring with flower design that has a 10mm pearl. That seems like a good maximum to me. I am buying a south sea pearl pendant at the moment that has a 12-13mm pearl and the coordinating ring has a 10-11mm pearl, just for reference.