You'll likely be eating ramen (and vietnamese sandwiches and dimsum) all the way for the entire summer no matter what. With an additional mouth to feed, you have a lot less runway.
She has to focus on getting optimal grades, you have to focus on your startup -- maybe hyperfocusing on separate challenges and then re-uniting will be best for the relationship in the end?
TBH fairly small - but there is a difference between profitable and being able to get hold of some capital (beyond the seed funding of YC). You might well get to that stage (no - you should get to that stage :D).
Is there any reasons the GF cant come to the bay with you?
EDIT: cheeky but does the GF have any hacker skills to become a cofounder?
I think the idea above of asking your GF to help could be a good one. Maybe she has hacker skills. Maybe she has other skills which could really help your startup - business, sales, visual design. Any and all of these could really give you a boost.
Having a look at your responses throughout this thread it seems like you're looking for reasons to go rather than reasons not too.
Starting a startup is a huge commitment, potentially a lifelong one depending on your idea.
If you're even slightly unsure (which you seem to be), you should perhaps maybe think about it some more, or start it up from where you are.
I'm not trying to make you depressed or anything mate, but when things aren't going according to plan and everything goes wrong (as things can do with startups) you still have to be willing to give it 110%
So yeah, read some of the advice in this thread but really sit down, have a LONG HARD think about it. If you're prepared to make sacrifices (which there will inevitably be, it's your choice what they will be though) - then make a decision.
Wait until she's out of school? I found that my girlfriend's world view changed considerably when she graduated and had to get a job. She was much more understanding after that.
But managing two households at once on $5,000.00 that YC offers is hard work. I would be eating ramen all the way for the entire summer.
Whats the percent chance that your actually profitable after 3 months worth of work.