Jessica - yes, 'a friend of mine' is absolutely correct.

And to explain Andi's correction, you can't use a present perfect tense (have been) with a past time phrase (yesterday). You have to use a past simple. You could either say 'Yesterday I was at the wedding..' or 'Yesterday I went to the wedding...'.

Roman - I'm sorry, but the phrase 'one my friend' means nothing at all. It doesn't exist.

 Hi Jessica,

I love weddings too, though the days can be so long and after dancing all night I only want to crawl into bed and sleep for a week. Wet bride, lucky bride seems to be an Italian phrase, and in nations like England or Scotland it would definitely not be considered a lucky omen :)

I grew up in South Africa, and we had a saying, it's a Monkey's wedding! This wasn't an actual wedding, instead we said that when the sky was blue and it rained, and then we saw a rainbow. 

Correction to your note:

Yesterday I was at the wedding of a friend of mine. It was a fun day, even though the rain didn't stop. It was cold. In Italy we say; wet bride, lucky bride. Is this the same in English?

We sang, danced, and toasted the happy couple, and afterwards we partied at a nightclub.

On the subject of weddings and bad weather, I once went to a wedding when, just at the most important moment of the ceremony, there was an enormous clap of thunder outside! It was terrifying, and quite worrying. But fortunately, the best man made it sound positive in his speech later on.

Su.ki: Oh, you're right... Sometimes I forget something about English grammar. :O 

Thanks to all!! 

In my place people also believe that if wedding day is rainy, the couple will be happy in their life:)