Can you show symptoms of mono before 4 weeks?

Fortunately I know some exact dates. Met a girl on the 14th of August, kissed her then and again 1 week later. I was told a few days ago that she had mono and was in bed sick. Now it has been exactly 6 weeks since we first kissed and I have not shown signs. However, around the 30th of August I had such a sore throat that is was actually really really hard to swallow, painful too. I had that sore throat for about a week or two, and my neck lymph nodes were swollen then and are still a bit swollen. But that was only 2-3 weeks after I met her. I really don't wanna be showing signs now, I have a really important month ahead of me. Does it sound like I got the symptoms over with early? I hear the incubation period is normally 4-6 weeks. I am 20, male, and have a good immune system (from what I've seen in the past)