Any gold-diamond players feel like speculating a match ?

Im leveling up a new account (my last one i havent been on in years/mmr was prob very bad im sure since i didnt take time to learn the game.) I have been on youtbe watching coaching/diamond replays of my champ pantheon. I do feel better while leveling up this account although still a little unsure of what to do sometimes. Last game i laned against a Silver 2 jarvin. I outplayed him and got f blood. Unfortunately we had a jhin top and a akali adc and the jarv would just roam and wreck, I mean i roamed as well and got kills but i couldnt stop him. I wanted to blame my team comp at first but then thought well hey maybe a better pantheon would have no problem with this match.. what would he do??

So maybe if someone can speculate a match and give me some tips I might be able to save myself from future failures. I know its a lot to ask so if anyone is up for it I couldnt be more thankful. I will be on tonight my username is Toptarts, Add me!