Ignore the pearl-clutchers! It's fine! Of course you can wear a light grey trouser suit to a wedding. It's chic and modern. I'd much rather someone wore a trouser suit like this to my wedding than an identi-kit floral dress and hideous fascinator.
You'd best have a dress-code then.
And do run it past posters here:
MN just loves a good dress-code thread.
I haven't seen any pearl clutching (personally, I only wear diamonds and those only after 6pm).
Just things either saying the suit would be fine or maybe it's not fine (especially if you're having to ask a load of strangers on the internet) although you'd doubtless look lovely. And so forth.
Funnily enough, yours is the most "pearl clutchy" post I've seen*: adjectives like "identi-kit" and "hideous" for what are probably perfectly fine dresses and headgear.
Ultimately, the OP will make up her own mind and, in the meantime, don't take it as a personal insult if someone has a different opinion from you.
*Apart from mine about Cara Delevingne. Oh, how we sniggered.