I also read Homestuck for the first time fairly recently and as a legally-an-adult, so I can confirm it's still super fun even under those conditions. A couple... unsolicited pieces of advice, I guess?:

Pay attention to details. This a story that rewards having a good memory, and may expect you to remember something that happened a while ago without reminders.

If there are concepts or characters to which your initial reaction is "I don't like this", give them a chance. They may surprise you. (Not referring to anything in particular here, just Homestuck in general.)

Also, I know this is a weird and perhaps rude thing to say to someone saying "I'm chronicling my reaction to Homestuck", but if you haven't already, and aren't too far along in Homestuck, I might actually recommend reading the author's previous story, Problem Sleuth, first? It's short (relative to Homestuck), very fun, introduces some running gags, and, IMO, acts as a good lead-in to Homestuck. Being as spoiler-free as possible, the beginning of Homestuck is much more Problem Sleuth-esque than Homestuck-esque. In my experience, reading PS first made it feel more like a gradual transition, rather than being thrown in the deep end of a pool at the start of a driving lesson. (There's also the first two MS Paint Adventures, Jailbreak and Bard Quest, but they're... not great.)

Regardless, I really hope you enjoy! It's a great story.