Good C++ experience, good algorithm knowledge (sometimes a problem for experienced programmers who don't often have to think about performance), and good attitude will likely get you a job at many companies like Facebook or Google easily enough.
Being confident and doing your homework about the company and the position, and otherwise being prepared is probably all you need, as well as being responsive and proactive with your recruiter. There's no real downside to applying - it'll give you confidence and a reality check even if you aren't given an offer, and prepare you for later interviews.
Some companies (like Facebook) may allow you to choose which team you join - find that out in advance, or know which team you will be joining when you are interviewing.
Even if you don't immediately get to work on the team which does the Big Data work, most good companies will allow you to move around once you have proven your skills and fit, especially if you show a strong interest, speak to the right people, and contribute.