Chevy, you are way too kind, KMBR, you need to learn the Marth MU, and honestly you just got better playered on. I personally have played Ether in melee and he is a heck of a good player, and would never drop a game to someone that doesn't know marth half as well as he does. There are a ton of things you can work on in your game, and you should take the time by watch other melee and Pm samus players as to what to improve on as well as what they do differently from yourself. You definitely need to work on your recovery game and avoiding being hit before or during or grapple, and if you can't sweet spot that ledge at least 70% of the time with your up b, you will not make it far in tournies. You also need to use something called a shield, which is useful for not getting hit by attacks, samus has a very useful out of shield option, called up B OoS, where the first 4 frames are invins, and its a very quick and safe option a lot of the time when someone is pressuring your shield.
THAT BEING SAID, it being your first tournament, you did not do so poorly against such a veteran player, and you do have fairly good of control of the character, your basics just need a lot of fine tuning, keep at it and you will continue to get better.
*Another thing to add, commentators don't know wtf they are talking about, getting an ice upsmash against marth... OK GL WITH THAT... :/ the beam styles are more user preference, and I would say fire and ice are about the same in usefulness in the marth MU, (unless its a stage where with low platforms where you can spam the **** outa marth with the ice missiles, which I would say Ice is better)