Don't rush. Take your time. Let it grow.
Well, that and,
There were agents who specifically asked for what you write three years ago and there still will be three years in the future.
The thing about it though, is, it isn't easy. I'd rather just send out some queries, have a few agents say I'm wonderful and then end up on a bookshelf with a shiny cover and big letters with my name on it. At least, that horrible, awful, no good, very bad side of me says that. The sane side says what's in bold. I really don't want my books to end up on bookshelves right now. They're not ready and neither am I.
Don't rush. Take your time. Let it grow. There were agents who specifically asked for what you write three years ago and there still will be three years in the future.