My mom is going to her boyfriend's son's wedding in November. She gets along with both the son and his fiancee perfectly fine. She's just not sure if she is supposed to get a long gown or a regular knee length dress that she would wear to anyone's wedding. She will most likely be in some pictures but she doesn't want to look like she's trying to be one of the 'mother of the groom or bride'... any suggestions? She of course wouldn't get a 'mother of the bride' type dress, but we both feel that a longer dress is more formal 'wedding partyish' than a short dress....