I am lucky to find the phonetic structure of Esperanto extremely close to home, but a stress in the middle of a word has always been alien to me. (I am inclined to read everything I see with a stress on the first syllable and only expressed through loudness (no change in pitch or length or articulation), even in English I sometimes have to actively think of not doing so.) I also have some trouble detecting it in others' speech, unless it's really accented. I have not yet had a chance to have my Esperanta pronunciation assessed by anyone and I am afraid that I may develop some bad habits by not paying enough attention to it in the early stages.
In some recordings I have heard (throughout my course on Duolingo and randomly scattered on Youtube) I couldn't really say the people would put very significant stress on the penultimate syllable, but that may just be a result of my indisposition. When I try to read aloud and force myself to put stress on the penultimate syllable it feels somewhat strange (and I would say the same sentences actually sounds different from what I heard in those recordings).
My question is, may other people's understanding of my Esperanto be impaired if I don't do the stress right? Can it make hard for them to e.g. detect word boundaries? Or is it not so enforced after all?