Suspension setup not ideal. What should a noob do?

Long story short I bought a Scott Scale 730 Plus which I bought on a whim after a pact to give the sport a try picked up real quick. This btw is my first bike... like i said it was on a whim dunno why I just liked it.

After riding a few times and reading about properly setting up the bike i tried setting the sag. The fork is XCR RL-R or something, but it doesn't seem like it will sag on the lowest pre-load setting... I don't think i weight enough (120lbs) I think its a coil so I asked suntour if they have the lighter spring and they said 6-8 weeks they will have 120mm lights springs... I am also aware its not a very good fork...and im an idiot who probably should have researched it before hand.

Should I wait for the spring or try an upgrade it out right? Worried about upgrading it since forks are expensive compared to the overall price of the bike.