Best Answer - Chosen by Voters
The meaning is a) As people get older, love fades. The Nymph is telling the Shepherd that even though he is promising all of those nice things now, time will pass and it won't be as important. The nympgh is basically saying "If this were true, then I'd waste my time living with you... Too bad it isn't."
Have you read "The Passionate Shepherd to His Love?" because this poem is actually a reply in which the nymph declines the shepherd's offer.
Edit- I just thought, that perhaps it could also be d, and the nymph could be insinuating that in the folly of youth, love is possible... but once people age, they become wiser and understand that love is impossible.