Should someone outside the wedding party give a toast?

So some good college friends of mine are getting married and it was up in the air on who would be the groomsmen after my friends first choice (a cousin) ended up going to prison. My friend ended up picking an old roommate for the best man job but told me he was torn between picking me or another close friend but didn't want to hurt any feelings so he picked his old roommate. Well soon after this I went on a planned trip to Ireland to do some soul-searching and while over there I did a lot of writing about love and ended up writing a toast for my friends. When I got back I went out drinking with my friends and I ended up letting these two friends that are getting married read the toast I wrote. Well they ended up loving it and they insisted on having it said at the reception. So now I am down to read this toast I wrote after the best man and maid of honor give their toasts. Is this normal or ok for me, someone not in the wedding party, to give a toast. I mean I am really glad my friends liked my writing enough to include me in their wedding like this and I am already down to help the groom write his vows since he isn't very good with words. I guess I'm just looking for opinions on whether this is ok for me to give a toast after the wedding party?