You can almost certainly expect to be nervous. You’re being asked to perform a series of complex tasks, and it’s not a simulation.
If however you’ve done a lot of your homework beforehand, you will feel better prepared, and this will certainly help to put you more at ease.
The lesson generally starts with a briefing and you will be given a list of objectives that you need to meet for that particular flight. Then you get your hands busy and start to practice the actual maneuvers!
Following the flight, your instructor will debrief and explain how well you did and where you need to improve.
But it’s worth noting that you will be doing a lot more than simply taking off and landing, you will also be learning how to fly straight and level, and how to take basic turns.
Ideally you should already be very familiar with the aircraft before you step through the door. In ground school you will have gone through the familiarization process and know which controls are where and how to use them.
But regardless of how familiar you are, it can feel a little daunting. But you should be put at ease by having a very experienced instructor beside you who can take over at once if needs be.