The Cardiff-born back is full of confidence after starting in the epic win over Toulon at the Arms Park and then being called up by the senior Wales set-up for the first time this week for the autumn internationals.
However, he admits he has been pinching himself with all that has happened over the last seven days.
"It's been a pretty surreal couple of days to be honest since beating Toulon," said Allen. "I hadn't really got over that and then the Wales call as well; it's really topped off probably the best couple of days of my life.
"I haven't played at Ravenhill before but I've heard it's a very tough place to go.
"We've just beat Toulon, but Ulster have also had a really good win against a top French side as well so they'll be on a high just as we are.
"It should be a real good encounter. Friday night rugby at Ravenhill, from what I've heard, is a pretty tough place to go, but I'm looking forward to it.
"Ulster have got a few Ireland internationals and they have quite a young side, quite a young back line. But they've got some pretty talented overseas players like Ruan Pienaar. It's a completely different challenge to Toulon but by no means a smaller challenge.
"This season has gone really well for me," he added. "Phil (Davies) wanted to give me a chance and he's backed me since the start of the season.
"I had a couple of benches, which I think I needed with the pace of the game, but then I've had a couple of starts.
"We've had a few disappointing results, but apart from that it has been a really positive start to the season and it just shows what our squad is capable of in that performance beating the European champions."