Alongside?

Could you help me to clarify the meaning of 'performing experiments alongside college students' in the following context:

In seventh grade, when Sara had shown an interest in science, her father had found a biology professor at the college who needed his main water line replaced. The professor tutored Sara in exchange for the work. Two years later, a chemistry professor needed his whole house replumbed, and Sara was performing experiments alongside college students.

Does this mean that she was performing experiments as a return favour provided by the professor, or did she become a college student?

p.s. her father was a plumber, and she used to help him sometimes in his works. Afterwards she graduated from Medical School, and became a doctor

Thanks!