Baring in mind my kids are like DownbytheRiverside children.
Your friend sounds nosy, she sounds as if she wants 'bad' news from you, so she can gloat! so you can either,
a) rub her nose in the fact your ds is not in trouble, but needs help coping with his cleverness, which while true is really not to be recommended and is certainly not a nice thing to do.
b) Go for the vacant, non commital little white lie and say 'oh, I missed a parents evening'
or c) and (bare in mind I have had to take ds as a toddler, and my ds has SN) take your toddler with you.
Me, I think I would go with C. Unless it is an educational tribunal, your toddler will not be in the way.
Because, she will be pissed off, if you tell her A) and will probably accuse you of stealth boasting. While with B) you could get caught out with your white lie in the future.
I have learnt after years of being an open and honest person, that people only like bad news, and they will beat you with any stick they can. That goes for parents of SN kids, (which is all, my kid has more SN than you) to the gifted kids, (which are all, ooh my dd got more A* than your kid at GCSE.)
Oh shit, I sound jaded and pissed off with life.
Actually, you know in your gut what you want to do, follow your gut.