Internet lag help asap

[divuxhd]

I have 25mbps internet I don't have issues with it when I'm alone but with 4 others in my family using the internet its pretty hard since I'm a gamer and even 1 person watching a YouTube video affects me what should I upgrade my router or change my plan to 50-75 mbps thank you

 

[Evil Mastermind]

First thing first is it wired and are you the only gamer