Howdy, I'm about 3 hours in (just made it to the cargo hold) and I'm getting my ass kicked though I do feel like I'm learning and getting better. That all said, I'm thinking about rerolling on a lower difficulty (picked Hard) and with a different build (went mostly Psi). Thoughts? Psi seems difficult to manage and I'm hearing it's more of a veteran option. Wasn't able to use my first gun until cargo and now I'm feeling like I should have just gone marine with a bit of tech instead of Psi.

you can lower the difficulty mid-game, but yes, as mentioned a lot of times pretty much everywhere, psi is a bad choice for a first time player.

if you are going to restart, choose a marine, and pick the leftmost career choice each year, that will give you a free laser pistol that only needs charge to shoot, basic maintenance to increase its battery capacity, and extra strength to deal more damage with melee weapons. once the game starts, upgrade maintenance to at least 2 (that will allow you to keep the gun in decent shape, so it won't break), hack to 2 (allows opening of locked crates, and easier hacking of security systems), and research 1 (researching of basic organs to get the damage bonuses). from that point, it's whatever you want (but do avoid psi completely, not worth the investment with a non-psi character).

normal difficulty is recommended for first time players. also, the wrench is your friend.