I was in a very similar situation to you a couple of years back when Bloodborne came out. Of course, at the time Dark Souls 3 hadn't been released but I wanted to get into the Souls-like genre. So I bought Bloodborne for $15 a couple of months after it launched. And I enjoyed the setting and Gothic styling to it a great deal. The gameplay took some getting used to as my first Souls game but I got the hang of it and enjoyed exploring the world for the opening of the game. Then it happened...
I hit Father Gascoigne. And this wall was a wall I have never gotten passed. I've made more than 100 attempts. My play time in the game is well over 25 hours and I'm just stuck. I put the game on the backburner and planned on going back to it another day.
This year I got Dark Souls 3 in January. I'll say this - the difficulty of Dark Souls 3 is set a lot more immediately. The first boss and mini boss are all experienced within the first half hour of play. But it's a difficulty that scales much better with both character progression and gamer skill progression. I managed to work my way through all of Dark Souls 3 and even beat all the optional bosses in the base game. It was an amazing experience.
After having accomplished that I recently went back to Bloodborne for a couple of 3 hour stints of getting beaten by Father Gascoigne time and time again and have put the game on the backburner yet again.
But that's just my experience. A lot of what people have said about your play style with games does matter and I'm always a more defensive and methodical player vs someone who can react in the moment well.
Did you find the music box? If you talk to the little girl and get the music box, you can use that to stun him and get a few combos in on him (Two while human, one while transformed). In addition, I recommend running up the stairs when he becomes a werewolf to make him follow you and get some hits while he's still climbing the stairs. After, keep running and going down over the little shed, and repeat the process. As long as you have the upper ground (anakin), you can get a few good hits in.
He really is an intense first real boss, and exactly why I tend to recommend Dark Souls for beginners. If you're not outstanding at bloodborne, Father Gascoine is going to put an end to your session every time.
Even now, after beating the game a dozen times and getting the platinum, I still find him one of the hardest bosses in the game.