Christening outfit help!

[ChesterFuckingDraws]

My nephews christening is in 4weeks and I need outfit help, and I don't want to look like a fat lump.
I'm 5ft7, size 16 (32G) doing SW so I'm currently losing weight but not very quickly!
I hate my arms (and fat stomach but I can hide that with underwear)
What on earth do I get for the christening, this is my first one so I'm clueless.

Hopeful bump. Anyone any ideas?

Maybe a nice Midi A-line dress? And some wedges? That's what I wore last year to a christening and didn't feel under/over dressed. I have awful thighs though so usually go Midi... Plus don't like having too much on show when at a church.

Christenings are smart but not wedding smart so don't go too formal.

I generally wear something like cigarette style navy trousers, a shell top with 3/4 length sleeves, and a blazer.

Fab thank you. I'll get looking!