Welcome to the forum! A pearl engagement ring would be terrific. You definitely want to look for a ring that comes up the sides a bit to protect the pearl, and it would help if the pearl has a very thick coat of nacre or is solid nacre, like a cultured freshwater pearl or a natural pearl.
Good Luck and don't be afraid to ask questions. There's a lot of information on the site for you to "Seek".
Blaire