Lingerie sizing help!

Brandi

So in looking at lingerie online, some of them say "one size fits most." I'm 5'2 and weigh 115. Is this something that's going to be too big? Too small? I've never bought lingerie but want to surprise my boyfriend! Would you order online or prefer to try it on? Most lingerie is final sale so if it doesn't fit I don't want to waste money