What do I do if I really only figured out what I want to research just after applying I recently finished a round of PhD applications.

I always knew I wanted to do research, but when I applied I didn't know what sub-field of Computer Science I wanted to do my research in.  I was already out of school a year when I decided that I may never figure it out just by sitting around, so I just bit the bullet and applied to a PhD program with what I knew.

Naturally, a month or two after I applied, I realized that what I really wanted to go into was robotics, which I have very little experience in at the moment and which I didn't mention in my personal statement.  

I'm pretty good at teaching myself things.  Give me another few months and I'll probably be able to learn quite a bit about the subject, and I'd bet anything I could put together some decent projects that could make me impressive enough to get into a good robotics research track, but I've already applied to a bunch of schools and it's at the point where if I'm getting in, I'm not getting in for anything robotics related.

So, here are the options I see in front of me:


Turn down the offers I get, try again next year when I can be more focused and well-researched on which programs/professors I want.  This feels like giving up, and I'm always nervous about putting things off, especially for a year.
One of the schools I got into happens to have a good program for robotics, but I doubt my application was on any of those professor's radar.  I could contact professors from that school and ask if they'd want to work with me, but I don't know what I'd say with so little robotics knowledge.  Another school I applied to but haven't heard back from has an even better program for it, so if I am emailing professors, there's still time to email professors from that school as well.
Go to a school I got into, and just hope I'll be able to switch programs. 


I know I ultimately have to decide for myself what to do, but any advice is greatly appreciated.
I saw this sort of thinking/discussion all the time. Something like, I'm a second year Ph.D. student but I want to start another one, because X is big and I'm excited about it. This is a bad way of thinking about a Ph.D. program. 

Here is the thing: 

One of the main pitfall of PhD students is that they can't get their mind into one problem.

Here is another fact: 

During Ph.D. you learn how to think and read/write as a researcher, regardless what you are working on.

Advice: I say choose one among all the offers you get. Drop all, unless you have a pretty good damn reason for it (e.g., got a job at NASA). 

Answering 'what I want to do for research' always changes! Thats the nature of research. You can not keep up with all trends during Ph.D. First, you need to think, read, and write as a researcher; and you learn them during a Ph.D. Then, you can follow the trends as a postdoc or an academic.