What am I missing?

I’m currently a senior in High school, committed to study econ at Rice next fall. I’ve come to realize that getting into Rice is great and all, but it doesn’t really mean anything if I don't have some type of plan for employment post-grad. Naturally, with Rice being located in Houston, and  my wanting to make good money out of college, I made this super rough outline of my employment path: 

1. O&G IB Analyst: 2-3 years
2. Transition to a position at an Energy PE firm
3. Haven’t thought it through this far; go where the wind takes me I suppose. 

Now.

The difference between me typing out that  “plan” and actually executing it is like the difference between sneezing and crossing the Gobi desert. I don’t want to say I know anything, because there are definitely so many things I am completely unaware of when it comes to this field, but I know that IB is not for the weak. The 2-3 years I’m in IB (God willing I land a job) will be the hardest years of my life. On top of all of this, I have a girlfriend who I’ve been with for a long time now. I really love this girl and I genuinely see a future with her, so reading the IB + LDR horror stories in separate discussions, and the thought of those things happening between me and my girlfriend genuinely makes me sick to my stomach. 

With all of this being said: What am I missing? I am asking anyone with any experience  to tell me what I am forgetting to consider. Please be brutally honest. I want to hear how naive I sound, and why my plan might fail. Thanks in advanced for any helpful insights; I am looking forward to gaining a better understanding of the corporate finance world.