At least that has been our experience over the past few years.
Good luck either way, and make sure you graduate with good grades, regardless of your choices for college! Also, charge 1.5-2k/week and ask them that for the consideration of a discount you want to utilize their name in advertising or as a reference on future work. It is all your risk to deliver and do your job, but pays you back massively over time, not to mention rarely will people object to this if you do your job.
Also, exactly what does it take to qualify as a "professional" developer, by which I don't think you merely mean being a mobile developer full-time, but actually having some set of qualifications?
Also, the flat-rate model lets you ask them up-front, with no loopholes involved, for $X where X is constant and the deliverable is a static goal, Y (don't let them scope creep or else adjust X). Most importantly, you can ask for what you think the value is instead of asking the client to guess how much your vague hourly estimate and project estimate will wind up costing in the long run. They know it's X, no more, no less. Ask medium. Negotiate if it seems like you asked high. Resist if you want to gamble that they're on a fishing expedition or have reason to believe so. Ask X for Y and deliver Y and accept no less than X.
Charge hourly. Development will take at least twice as long as you think it will. I'd start at around $15/h.