The way i got it it was not really part of the prophecy..it could be interpreted as part of the mergind with the second half of the soul..but anyway..think about who made the prophecy. Valen aka Sinclair. His prophecies were based on what he himself saw in the future. In WWE when the White Star is going through the rift, there is a scene in which Delenn and Sheridan hold hands, Sinclair sees this and smiles, kind of like a proud father. So, also if there would be this prophecy and Delenn went after him because of it, that is only because they really would fall in love, otherwise the prophecy would not excist (I hope you're still getting what I'm saying)
Delenn making the moves does not necesarily mean that she's just folling a prophecy and he's initially not interested. Consider his situation. Also if he is very attrakted by Delenn, consider (a) he just lost his wife Anna, who he had truly loved, a few years before. He's not over her jet and IMHO he only truly gets over Anna when he dies at Z'ha'dum (b) Consider his special relationship to the Minbari at this time in the series. In general, they hate him. Would you make moves to a relationship with the ambassador of a species that in general hates you, wants you out or even dead?
All that said, i think it is obvious that there is mutual, genuine love between them from the start. Just look at Sheridans gaze in Revelations when he meets Delenn for the first time when not being about to be executed (ITB)
I remember when i saw that episode the first time when it initially aired here (I was on B5 from the middle of the 1st season of the initial airing) i noticed that there was something in the air when they meet.