In my current part-time work situation, we have weekly meetings where we discuss our ongoing progress. I often present my work along the lines of "I had a pretty busy week so I wasn't able to accomplish as much as I would've liked, but this past week I was able to x, y, and z, and from here I'm planning to work on a, b, and c." My manager continues to express satisfaction in the progress I'm making, and I am meeting all expectations so that is a non-issue.
I've been unsure whether I should continue to mention my reasons for not meeting my personal desires. On the one hand, I feel that it helps encourage understanding within my manager, so they keep in mind that I'm a busy person and to manage their expectations accordingly. It might also help them understand when my work is challenging if I explain that my slow progress is the result of a difficult problem, not out of laziness (I am working outside of their area of expertise or familiarity, so they don't know what is hard to do and what isn't).
On the other hand, I'm worried it might have some long-term effects on how they perceive me. They might remember me as the "didn't accomplish much" person, or the slow worker. I don't think they'd do this on purpose, but I'm worried it might sneak into their mind if I continue planting the idea so often.
Given that I continue meeting expectations of my manager, should I continue explaining my reasons for slow progress (as applicable), or stop this practice?
For some background to my specific situation, I am an undergraduate researcher at a university. I am the research team's sole software developer. I am currently unpaid for my work (hence the low expectations), but that may change in the future. The reason I ask this question here instead of the Academia site is because I feel confused on whether I should do this also once I'm in a normal job, so I feel it applies to the workplace more generally.