All awards are available to all ranks.
Obviously you aren’t starting with any of these, but if there’s family background it might become relevant...

+4 reaction

Victoria Cross: you did something really impressive in the face of the enemy, and probably died as a result. Even in the big war just gone, they only awarded 100 or so, and the vast majority went to ground forces. In the Navy, this usually means personal fighting, such as a landing party that gets involved in an infantry fight, a spotter for orbital support fire, etc.; it is also awarded for those rare situations where someone is the lone crewman on a ship being used for special purposes.
George Cross: “acts of the greatest heroism or of the most conspicuous courage in circumstances of extreme danger”; in a military context this usually means gallantry not in the face of the enemy. Again, often posthumous. The canonical example is the engineer who stays behind to keep the reactor from cooking off while the rest of the ship’s company evacuates.

+3 reaction

Distinguished Service Order: for distinguished leadership and command.
Conspicuous Gallantry Cross: next step down from the VC, “in recognition of an act or acts of conspicuous gallantry during active operations against the enemy”.

+2 reaction

Distinguished Service Cross: next step down from the CGC. Descendant of the Conspicuous Service Cross. Military Cross (for shore actions) and Distinguished Flying Cross (for small-boat actions) are also possible, but rare.
George Medal: a step down from the George Cross; gallantry not in the face of the enemy.

+1 reaction

Mentioned in Dispatches.