Definitely attend every SA event you can. Go to the desks of your representative and both senators and ask if you can provide your contact information if they have specific SA events.
Several of the people DS had met at SA and ROTC tables at SA events turned out to be on CO MOC interview boards. Your own BGO, ALO or WP liaison can't be on the MOC board reviewing you...but that guy you've met 3 times who is BGO for adjacent high school or a retired ALO who skill keeps his hand and introduced you to some cadets may be on one of your panels. It's not going to EARN a nom for an unqualified candidate, but DS felt it didn't exactly hurt when a respected retired Navy Captain welcomed him with obvious familiarity to the interview. (Noms to both USNA and USMA)
Speaking as a recruiter (not military), emailing early is fine as long as you do it intelligently. Clearly state in first sentence that you're going to be one of their applicants next year for class of 2025. Confirm you have reviewed their SA MOC NOM process on their website and just want to be added to email contact list so that you hear about summer/fall SA events the MOC is planning. Our district has a new Representative and at his first SA night, there were only approx 20 candidates there for all of the SAs. I don't think all of the liaisons in our district got the word.
One other fun thing about SA events--you may see these kids at NASS or USAFA summer seminar or SLE.