I know that 18 events, or 3 years (MJ usually runs 6 events a year) might not seem like a lot for a character but in the world that has been created you can truly accomplish a lot in that time..... or feel like you've accomplished nothing depending on how involved you choose to get with things.
The crazy thing about MJ is that while there are a lot of people who have managed to live for over 10 to 15 years as their characters, there are those who die in 4 , 6, 10, etc. events. It has a lot to do with the type of character you make, as well as a mix of luck, chance, and karma that your character builds in the world amongst friends as well as enemies. So maybe you can make a character that lives really hard (tries hard, has crazy conviction, fearless, etc.) or someone who just really wants to live each moment until they burn away. 3 years sounds like a great opportunity to try an extreme type of a character if you ask me.
Speaking from only my own experience, I can say that the first few years of this game were pretty crazy awesome for me. It's still pretty great and I've really come to understand so much about myself and my character as we've shared time together. Both personal growth and character growth came most dramatically for me in those first 3/4 years (I chose to work on personal things through my first character which was amazing but not without challenges).
On the flip side, I also was a cast member for about 2 years before I became a player. I already understood a lot of the mechanics and had a great understanding and respect for the people who bring the world to life from the npc and crunchy standpoint. In my opinion, this experience brought a greater depth and empathy on my part towards the general cast members because I knew what it was like in to be in their shoes.
That's a lot of words to say that whatever way you go about it, I don't think you'll be disappointed..... but maybe hold off on the custom plate mail armor set for now