To expect an acknowledgement to an invitation

[AngelThursday]

Sent my sil an invitation to join the rest of the family for a buffet tea on Easter Sunday. She is my DH's sister and the other people coming are all his and her siblings plus partners, their parents etc so the family are all from my in-law side if you see what I mean.
Sent her an invitation via Facebook messenger last Saturday ie over a week ago and have heard nothing but I can see the message has been read. To be fair she was on holiday at the time but was updating her Facebook status several times a day. Since she returned on Thursday I still haven't heard anything.
I realise it's a while ahead and that people have busy/complicated lives but Aibu to be offended not to have received an acknowledgement of the invitiation? Even if only to say, hi Angel got your message, thanks, but not sure yet what we're all up to at easter? Personally I think she's being a bit rude. All the other siblings and DH parents have replied. Some have offered to make food for the buffet too

She probably forgot- quite often I reply in my head but not in reality. Just send her another message or ring her

I've done that Playmobil but still nothing

Yes I'd think it was rude. I'd probably post something on Facebook about looking forward to the buffet tea and seeing and omitting her name. Maybe she'll respond then?

Would really appreciate a few more comments ...

Get your DH to phone his sister and ask her.

Can you not just give her a call?

I think 8 days to reply isn't that long considering its still a while away. Give it a few more days and then just ask again.

I am rubbish at remembering to reply to stuff like this. Just give her a call, she probably has kept meaning to reply and kept getting distracted.

Did you give her time to reply by? as in "let me know by x date.

I made comment on an earlier thread, I really don't understand texting - if you want a reply, phone her and get one. A text would go right to the bottom of my to-do-list.

She/they well may be waiting for other commitments to fall into place.

I call her? Text her? Maybe FB playing up?

Thank I'm terrible at replying to FB and email messages. I look then intend to reply later. But then forget as they just disappear or get lost down the list.

What'sApp or text I'm far more likely to get another message then realise I've not replied to a previous one.

Don't be offended. SIL probably doesn't think she needs to RSVP a whole month in advance.

Next time you see her, you could always ask what her plans are for Easter?

Why make life complicated. Just pick up the phone

Give her a ring.

There's any number of reasons why she may not have replied yet.

You sound as if you are looking for a reason to be offended.

Ok so it sounds like most of you think I'm being impatient. I can't text her as I don't have her number (complicated back story, we fell out as families a few years ago and since then do not have each other's mobile numbers) and she doesn't have a landline. I'm not looking for a reason to be offended. I was expecting an acknowledgement of the invitation, not a reply per se. I know she's read message cos it shows up as such on messenger and that has always been the way we communicate recently. DH can't phone or text either as he is in the same position as me.
As you can see, a slightly odd and tricky family situation!

Highinthesky - I won't see see her before easter. We see each other once or twice a year at family get togethers.