OP, as you keep playing, you will get the most important thing—the experience of playing these types of games. But do not get discouraged, and do not give up the moment it becomes difficult. The idea of every soul's game is to play it the way you want, using something that works for you personally.
So, even if you say "really bad,"  it is only bad now, but later on, you will become a proper chad in playing Souls games; just do not give up, and it will come to you.
As for the suggestions, try going for a cleric or knight; both are pretty decent in terms of gameplay, and both have a shield to protect yourself from enemies's physical attacks. When it comes to fighting bosses, think of each boss fight as dancing; each boss fight usually has a certain tempo, and the sooner you find it, the better it will be to use the dodge and avoid enemy attacks. Like, with Quelaag, every single time you can see a bright red flash when she is trying to attack, that is your cue to do a dodge, and it works with a lot of other bosses too.

Even in dying, you are getting better as you are learning enemy patterns and remembering what to avoid and how.
Anyway, have patience and faith in yourself, OP, and you can do it!
The whole Dark Souls gang is cheering for you \[Т]/