I don't see why not. I only have a 100Mbps plan in my home and I have no problems at all with me, my mother, my nephew all on PCs online while my niece and sister are on their phones browsing or streaming simultaneously, or streaming Amazon/Netflix videos or downloading whatever is needful.
Even for 3-4 devices with occasional large downloads, HD quality streaming and multiple users places like highspeedinternet.com only insist that something around 40Mbps is "recommended" so 300Mbps is totally fine. More important is probably ensuring that your service is through a company known to actually provide consistent throughput that is at, near or above the advertised speed. 300Mbps plan isn't much good if you're consistently only getting 25Mbps so make sure it's somebody that has at least moderately good service like Verizon or Xfinity. And no, I'm not talking customer service because we know just about all of the big players suck in that regard these days, just actual service.