Mario: [Great] The first time I have seen Mario was in a cartoon, so when I found out that he has a game, I thought that all cartoon characters you see on TV have a game based on them, since I also found out that Sonic has a game too (coming from knowing him in a cartoon). The first time I heard Mario's voice, it was surprising to hear a falsetto because it's unexpected, but it felt like it fits Mario very well.
Luigi: [OK] I felt that he has little presence, since I don't tend to play 2 players. As such, I didn't view Luigi to be an important presence in the overall Mario world. Even back then, I believe I knew that Luigi looked similar to Mario since it doesn't take much effort to implement him that way.
Peach: [Invisible] I never knew the princess character is supposed to be an important one, because not only is her presence lacking in quite a number of Mario games, her design never stood out to me. Even her voicing felt like standard fare. Even now I found Peach to be very generic compared to the rest of the Mario crew.
Toad: [Great] He is what defined Mario to me because of the distinctive mushroom cap, and despite its simplicity, is very recognisable. Only thing is I didn't know that Toad is part of a species, as I thought there's only one Toad. My first impression on his voice in Super Mario Advance is one of excitement because he made a very distinctive sound, and one of my favourite voice acting.
Bowser: [Invisible] Similar to Peach, I never knew that Bowser is supposed to be an important character until the later games where Bowser is more easily identifiable.
Daisy: [Invisible] I never knew that Daisy was a notable character until I read up on how the spin-offs have her, most notably Mario Tennis. My first impression on her voice is strong however, so unlike Peach, I eventually liked Daisy better mainly because of the voice acting.
Yoshi: [Good] Very useful, since he's like a horse that you can ride on. His record-scratching voice is a mystery because I can't seem to imitate it very well.
Wario: [Good] I love how wacky his name is, because it so similar to Mario that I knew that he's a sort of rival to Mario. His design is also very good so Wario's off to a good start. His voice acting also felt natural for the type of person he is.
Donkey Kong: [OK] My first impression of Donkey Kong is from the CGI animated series, where he's funny to look at. I don't remember the singing part but it's amusing to find out that the singing is what made the animated series' DK very memorable. In terms of video game voice acting though, the monkey sounds are very funny.
Waluigi: [OK] I was reading about Mario Tennis on The Mushroom Kingdom and I found out that there is a character called Waluigi, and knowing that Mario, Luigi and Wario exists, the addition to this character clicked with me because he fills a gap that I didn't even know was there.
Bowser Jr.: [OK] It was kind of unnecessary for Bowser Jr. to be included, given that I knew that Koopalings were established as Bowser's children (as they were known then). I came around when he provided a more continued presence since he's clearly built to be Bowser's partner-in-crime.
Toadette: [OK] Much like Waluigi, Toadette filled a gap that I didn't know was there, so I am good with her inclusion.
Rosalina: [OK] I thought she was an alternate version of Peach at first. Also, I liked that there is a new character introduced for the latest of Mario's most exciting adventure (at that time).
Thank you for reading.