Quick Question

With as little information as possible, am I screwed? Also, sorry for the paragraph, Im just legitimately scared.

Just some context, Im trying to defeat every boss on my first playthrough to have a sense of completeness by the time I finish. While Ive had to look up boss pattern guides for some bosses, none have given me TOO much of an issue. I just defeated yon tiger after my personal record amount of attempts (12). Do any of the bosses (either story or secret) Get significantly more difficult than the Yin Tiger. I should add that ive never really played a souls game or any notably difficult game in the past, and i have given up on playing becayse of difficulty. Without naming any names, do bosses get considerably more difficult than the yon tiger or do they remain the same level. Take this post with a grain of salt because Im aware that the player gains new spells and experience throughout the game which might make new bosses more achievable. Im asking because Im having a lot of fun for the game and I dont want to get stuck on a brutal boss fight and give up playing all together.