Is the use of the introductory word first awkward or confusing in the following paragraph if I don't include another sentence starting with secondly?
In the process of learning them, I deeply felt that there were many more obstacles to overcome for girls than for boys in order to learn technology. First, generally speaking, girls are not as good at logical thinking or as familiar with various softwares as boys are. Another related fact is that professors tend to hire boys as their research assistants, which means that boys are given more opportunities to practice their technologies.
I do not use secondly to follow the adverb first. Do you think this makes my writing less clear? I myself sometimes find the use of "first, second" awkward.