As your questions are broad, so shall be my response.
If you’re serious about pursuing undergrad/grad studies in psychology and in practicing in some capacity in the distant future, prepare yourself for major changes in the field by the time you are licensed and ready to hang out your shingle. No one knows what the profession (an exceptionally broad, imprecise term) will be like in, say, 10 years, but if you are a direct provider, managed mental health will certainly continue to force changes, some unwanted. BTW, if memory servers, I believe “psychology” as a declared major among incoming freshmen ranks in the top five.
As you will eventually be required to focus your studies, are you more interested in direct clinical work, research, academia, industry, policy, or what?
First, I would suggest you analyze very precisely why you want to be a psychologist. In other words, what is driving you, other than some vague interest? If your desire is to “help others,” why specifically as a psychologist? Plenty of professionals help people. If your goal is to cure others, consider a profession as a physician or financial adviser. Curing is not part of psychology.
If your goal is primarily focused on money–as Q. 2 implies
–realize that some psychologists do fairly well, some do rather poorly. Depends on lots of factors. Also this: many individuals who undertake the long journey toward being a psychologist discover along the way that the profession wasn’t really for them after all. Is your personality suited for the profession? How so? We could go on like this for hours…
A doctorate in psychology can take anywhere from eight years to never. Depends on your aptitude, the university you will ultimately attend, your advisers, etc. Competition for entrance into the better grad programs is exceptionally keen. Plan on scoring in the mid to upper 90th percentile in your boards. Are you interested in a Ph.D. or a Psy.D.? Figure four years for undergrad, plus at least 3 for grad–but more likely 4 and possibly six.
Re: licensing–call the state licensing board. Re: money–talk to three pscyhologists in the area in which you want to focus. As grad school is rigorous and you would not want to be at an academic disadvantage with others, a B.S. in pscyhology is probably a good idea. Of course, realize that the vast majority of persons who currently have that credential are not working in any aspect of pscyhology.
A message board isn’t the place to decide on the rest of your life. Talk to plenty of professionals. Good luck.