Rather than taking a course through a camera store or something, try a community college course. Community colleges are open to all, so no admissions issues, you just need your high school transcript.
Generally, the beginner's courses at community colleges are film based and so you will learn about using your camera but you will also learn about darkroom techniques. And so you will learn to process your own film. B&W is not only inexpensive to process yourself, it is also easy.
I will be taking my first photography class this fall. Once I learn my way around the darkroom, I am going to set one up for myself.
Taking one 3 hour class should cost you about $300 (maybe a bit more) at a community college and you would go for about 16 weeks in fall or spring and about 8 weeks during summer. Many people take courses to get training that they need with no plans to get a degree. You might be able to get financial aid.
One place that I have found where you can get decent feedback on images is on dpreview.com on some of the forums. I have never used the Nikon forums.
The problem with any photography forum is that you become something of a community and people really hate to say something that might hurt your feelings or run you off. But there are plenty of people on those forums usually who will tell you the whole truth no matter how pretty or ugly the truth might be. So, while you might get lots of comments on how that image of a sunset (which is similar to all the sunsets that have come before it) is just beautiful and great work, you will get a few grains of the truth as well and advice on how you could make it better.
Remember when shooting film to keep notes of the settings you used when you shot each picture. Then when you post them include that info. Otherwise the people on the forum won't know what settings might have worked better. (With digital, that information is recorded in the file so you don't have to record it.)