I am honestly very surprised by the early Heralds. Moreso for your opponent, but even for yourself, you only had two Junk Dealers when you got your first. And you got it on a 5. Given how many crucial engine pieces like Merchant Guild and Catacombs depend on 5, that was definitely a mistake.
Generally, you only need villages-even good ones like Herald-after you have multiple terminals in your deck. With the Fortresses supporting, the Herald split wasn't going to make a difference. Besides, there was always the risk that Heralding into a Junk Dealer would make you trash something you didn't want to trash.
The engine looked strong here, and I think you definitely had a better opening than your opponent, but always look for opportunities to improve.