He's (or was was anyway) an adult working male, and he's shaking in his boots because two cool kids from highschool are standing at the doorway? He's getting so flustered because a more childish version of an old friend hugged him and made a sexual joke? He couldn't even ask someone to hangout without coming across as if he was about to piss his paints! How lame is this dude?
Honestly, so far anyway, this chapter lacks any of the appeal that timetravel plots such as these should have; retaining a mature mindset, worldview, and amount of knowledge, thus being able to take advantage of situations that we couldn't in our youth. This is just an ordinary awkward teen romance, but with a timetravel plot preface tacked on.
I'll give this a chance, but I found the opening quite lacking, honestly.