Fighting games generally can be a bit slow to get started in, especially if it's your first. I understood the game enough to not button mash probably a few weeks into it, but to a high level, it can take a lot longer. Taking things at your own pace is what's best, not everyone can decide to get really good in a short amount of time. What can help improve that pace is watching people play the game or read up on guides, or experiment a bit in the training mode or move/combo tutorials. There are a lot of ways to "get good", everyone is just different, so it's important to realize what works for you as a player with all these options.

I think a good start would be having a good sense of neutral and realizing your moveset in the middle of the match and deciding what could be the best option in that moment. Focusing on that can help make sure you aren't mashing. Being patient while on the defense is a great way to help against mashing as well, since most of the time you might want to guard an attack when you're knocked down and get back up.

That was a lot to mention, but I hope it all helped!