Akiyoshi, you've literally already gone out with Lemon and found out that it didn't work and was putting too much pressure on her. (Though I don't remember if Lemon has told anyone the latter...) There's no good reason to think that it will be substantially different this time.
Like, even if they do get together, I can't imagine it working out better. There's nothing indicating that Lemon has grown out of her old mindset of acting inauthentic so as to become more likable. (And this chapter seems to remind us that she still is, in fact, popular!) So doesn't that mean she'd just do the same thing she did last time? She tries to hard to be a "girlfriend" that she ruins what made her comfortable with their relationship in the first place (that she could just be herself) and builds up so much stress that she has to "explode."
She'd probably be more mature about it all, considering the fact that she's an adult now, but there's been no indication that she's not going to just follow this same basic rollercoaster if she goes out with him again.