The Royals' shot-stopper was delighted to make his Premier League debut against Tottenham and is now focusing his attention on keeping his spot in the first team
McCarthy was drafted into the starting line-up following a raft of errors in previous games by usual first choice, Adam Federici.
McCarthy is now aiming for an extended run in the first team, before turning his attentions to challenging for an England spot.
He told reporters: "I hope I can get a run in the Reading team now.
"I played in the Championship last year and I've been wanting to play in the Premier League for a long time. It's a massive league.
"The game's a lot quicker so I was pleased to get a start and I hope I can go on and build from that.
"I just have to get on and play my best. Obviously I want to play for England one day and this can give me a good chance to do that."
McCarthy went on to describe his delight, after being told by manager Brian McDermott he would be making his Premier League bow against Spurs.
"I went training on Saturday and the gaffer pulled me aside and said I'd be playing," he continued. "He told me it was a tactical [decision].
"He said he didn't want me to feel that he was just pulling [Federici] out because he was injured, because obviously that would have an influence on the rest of the boys in the team. I was over the moon to make my Premier League debut."
Reading have made a poor start to life back in the top tier and take on West Brom, along with former Royals top-scorer Shane Long, on Saturday knowing that three points will be vital to their cause.
"We can take some positives out of the Tottenham game but we know we've got to do a lot better," McCarthy added.
"Shane Long's a top striker, really powerful, so it will be a tough game on Saturday."