Asking a professor for a job reference; is this a good way to approach the situation?

There are three professors I'm well acquainted with, that I'm considering asking if I could put them as my references for a couple of jobs I'm going to apply for.

Here's some background info;

One of them is a former high school teacher whom I got along with very well and with whom after graduation kept in touch with for quite a while. I've known him for 4 years (or 7 total if we count emailing back and forth every now and then after graduation) It has been 10 months since we last spoke however.

The other two are college professors from the major I'm majoring in, that I have had a class with.

One of them I used to email asking for help on assignments from his class and met with a couple of times during office hours. I've asked as well for his feedback and help in projects from other classes which I continue to do even though I no longer have him as a professor anymore. I sort of see him as a mentor and really admire him. He has told me a couple times that he knows I care and am very hardworking. I've only known him for two semesters however.

The third one has said as well, that I'm a very hard working student and put a lot of effort into my work. My projects were among the exemplary ones in the class and she even offered me a job to help her in a small project but a few days later apologized as she was no longer going to go through with the project and didn't need my help anymore. I've only known her for a semester.