Hi! Sorry if I accidentally posted this twice, I don't have very reliable internet where I live and things time out a lot etc.

First things first, my problem is totally my fault and I get that.

Second, here's the problem: Using google flights, I decided to book all of my flights over a three month period during which I want to travel using a combination of trains and planes, the brunt of which are with American Airlines. My itinerary is as follows:

Bangkok to LAX--LAX to Seattle--Train from Seattle to Portland--Portland to LAX--train from Los Angeles to San Fransisco--SFO to Chicago--Chicago to Minneapolis--Minneapolis to LAX--LAX to Bangkok.

So there's a lot of information up there and while I was booking, Google automatically assumed I'd want to go to Chicago from LAX since it was the last airport I would be landing in, and my being in a hurry, I didn't catch it until a few days later. Instead, I need to leave from SF.

I called American Airlines and was told that it would be about 600 dollars to switch the flight from LAX to SFO (no thanks), or close to 400 to simply cancel that leg of the flight and rebook elsewhere.

I'm left with two choices:

1.) Buy an 80 dollar ticket from SFO to LAX and catch the flight from LAX.
2.) Take a flight directly from SFO to Chicago for 125 dollars and miss the American Airlines flight altogether.

I'm really tempted to do the second thing because it's worth it to me to have more time in SF with my friends and I'm actually terrified of flying and the fewer planes I have to be on, the better. However, I'm nervous that skipping the AA flight altogether will result in some kind of exorbitant penalty fee or a problem with my return flight, which is also AA.

Can any experienced travelers guide me in the right direction? Thanks!