First BIAB last weekend

Well, we don't know any other details about your recipe, but in general, I'd say let it ferment. It will be beer. Possibly very good beer. And you've already spent the money on it, so why not see how it turns out?

 

FWIW, there's no need to move an APA to secondary.

 

Your bitterness will not be as strong as expected due to the dilution and decreased boil time but you may find that you really like the results. Come back with an update in a few weeks.

 

OP, I agree with this regardless of whether your recipe says to transfer the beer. (This is actually a fairly new practice that most of us share here in this forum. Recipe writers haven't caught up yet.) Transferring to a secondary only exposes your new beer to a potential misstep and incorporating air into the beer during the transfer.

If you are anxious to have another brew session and you have a secondary fermentor vessel available, use it for your primary on your next batch. BUT, be sure the secondary is large enough to gave adequate head-space for any krausen bubbles to stay contained in the container. If your secondary vessel isn't large enough, then you'll have to brew a smaller batch or just sit tight until your first batch is done with your primary fermentor. It won't take so long to ferment and bottle your first beer, and then you'll be brewing again.

 

So you'll have 3 gallons of an Amarillo hopped session beer? That doesn't sound half bad. In fact, that could be a little bit of all-right.

 

KEEP IT!!!! Post the malt bill please. I might recommend a dry hop based on what you're working with.

 

Alright alright alright!

I think that sounds like a pretty tasty beer myself. Congrats!