I've been planning on making her Main (Cannon) Armor be Full Steel Plate (Minus Helm) and matching Skyforge Steel Sword. I use those because it's the only Heavy armor that I actually like.
A partial answer... A Knight is someone elevated to the rank by a ruler (King, Queen, etc) A paladin is often also such a knight, but he's often more closely associated with a religious figure or religion in general. Paladins for instance often have the ability to, in RL perform the duties of a priest and in fantasy cast priest spells... Restoration school essentially, but perhaps some others like alteration, or Illusion that grants "courage"
It sound's like you have a backstory that you are fleshing out.
Well if you want the Galdur fragmment and doing the CoW isn't exactly what you want to do, just do the 1st part and say that they made you ...The Dragonborn??? an honorary member because they think Thu'um's are enough like magic ( which is almost what they say anyway) to warrant it. Being a adventurous and martially skillful person, you are along to help with any security issues that may come up. yada yada... it can be done with out, having to be a magic wielding character.
There ya go, you can always come up with a Rp reason to do something that would otherwise seem out of character.
At 19 years old there'd be few, if any, knights. A teenager, or someone in their early twenties, are more likely to be a squire. I mean, anyone hear of any teenage army generals? I ask because a knight is the equivalent of either a colonel or general. They're the top brass of ancient royal armies.
It'd be more realistic if that was her arc, to start off as a squire or simple warrior, then eventually become a knight. Realistically, there's little chance of that until at least her late twenties, especially her thirties. Alternatively, you could make her ten plus years older. You know, we don't become "over the hill" once we reach our late twenties/early thirties.
A warrior class is totally open to any age, armour or weapon type. "Warrior" is very vague, unlike a knight, which is a rank.
Yes, simple warrior, as in nothing special about her. How does she become a knight? Well, she'll have to prove her worth to a leader of some sort in order to be knighted.
Steel Plate falls on the "Light Armor" half of the Smithing Tree, but Steel Weapons benefit from the first Perk in the Tree.
Enchanting, straight up the center to begin. The right branch is IMO wasteful. The left branch is primarily concerned with the strength of an Elemental Enchant on a Weapon created by Our character.
Two Handed, just avoid the Weapon Type Perks as the benefits from the Perks are questionable in utility for combat. The Sweep attack can be difficult to pull off, and opportunities to use the attack are not that common.
I have not placed a Perk in the Heavy Armor Tree since 2012
for a "knight" character (of any kind) follow the http://www.medieval-life-and-times.info/medieval-knights/code-of-chivalry.htm
Relate gameplay to the code and you will be fine. I plan on doing a weapon and shield fighter with the code as a guide (no poisons, sneak and stealth related things (stealing lockpicking in towns) and no murder sprees).
Perhaps it would be helpful to point out that there is little functional difference between a Thane and a Knight, especially if the thane-hood is bestowed by a Jarl, rather than being hereditary.
Yes, a thane is the Skyrim equivalent of a knight, only done in a pretty crude way. In reality it would take a lot more than simply doing odd jobs. It would take great heroism and deeds to become a knight.