Weddingbee boards

I really thought Mr.Tal and I had put the bridal party to rest, but it seems not to be so. I thought it was too easy anyway really! :-) It turns out that he would like to ask another friend to be a groomsmen for him, which would give him 4 groomsmen. I have 3 bridesmaids and was pretty content with that, until he said he'd like to have a 4th in his party. I'll admit, I'm a little obsessive about even-ness, I know our bridal party doesn't need to be even but I want it to be. So Mr.Tal suggested I ask his SIL, who I've spent a little time with, but not much. She's already put it out there that she would love to help with any DIY projects I have, she's very nice, and I like her a lot, but we don't know each other very well. I'm seriously considering it, because I think it would be a bonding experience and a nice gesture, however, I'm a little on the fence because we don't know each other very well. What's a girl to do? Any advice bees?

I say ask definately-I understand the need to keep it even-I feel the same way.  Ask her-it will be fun!!