you're not bad at all. i agree with keeper on this. keep moving and try being less predictable. also use your tilts more. olimar's tilts are good for spacing and set-ups (f-tilt to f-smash, d-tilt to up-smash, up-tilt to n-air, f-air,b-air, or up-air). plus, they also have a good amount of priority.
up smash out of shield is olimar's best friend. at 35 seconds into your video, there was a chance to land a KO. keep in mind that once a light character like metaknight reaches 100 - 120%, they're in range for an up smash KO from any pikmin that isn't white.
another thing, sometimes it's better to be really aggressive when your opponent is within KO percents. on your first stock, you took a lot of unnecessary damage before you finally KO'd Metaknight.
to help your survival rate when you're at high percents is to grab. olimar's grab range is longer than most other characters attacks. use that range to your advantage. once they're grabbed, either do an up or back throw. this will usually end in death for the opponent (when they at high percents also) if the pikmin that grabbed is purple or blue.
