First time building and setting up a NAS!

[Ericloewe]

Yes, you will of course be limited by network speed. You should definitely wire the NAS. It might not be so bad though, the switches in even low-end gigabit routers are capable of gigabit speeds on just about all ports simultaneously. Those switch chips have evolved to the point where wired speed is not a great concern. Wireless hardly uses any bandwidth in comparison to gigabit. Your router can be quite busy with wireless data and still have lots of resources free for gigabit transfers since the LAN ports often use a dedicated switch chip or have this functionality built into the CPU, separate from the wireless hardware.

Of course you might get benefits from separating out wireless data and using a gigabit switch:

http://www.smallnetbuilder.com/lanwan/lanwan-basics/32056-how-to-improve-network-performance-part-1

but this might not be the bottleneck. If a wireless device is accessing the NAS, the bottleneck won't be the gigabit connection, it'll be the wireless connection. The same site I posted above shows the highest wireless data throughput they ever measured was a little less than 250 Mb/s. That's the very fastest 802.11ac under absolutely ideal conditions at short range. It's less than 1/4 of the gigabit bandwidth. Your gigabit connection won't be stressed at all. Even with several simultaneous transfers, the wireless radio will be so busy you won't get much higher than that in total.

Somewhat offtopic: In far less than ideal (thick concrete slab) conditions, I regularly get 200+Mb/s with three-stream 802.11 ac (though with no 5GHz neighbors).