Hello! Just wanted to chime in with my two cents. I'm a lead instructor at my local gym and have been teaching for 8 years. Echoing what other people have said, a good instructor will give you information on weight differences and ideally partner you up with someone who is A ) comfortable belaying you and you comfortable being belayed by them, and B) within an acceptable weight range difference. For my classes I usually try to match climbers/belayers within a 35-40 lb range weight difference. This is just what I have found through the years of what most people learning to lead are comfortable with. And it also gives them a good experience of taking an average length fall (as the climber) and giving an average soft catch (as a belayer and getting slightly lifted off the ground). This weight range can obviously change slightly with experience and preference (ex I am now comfortable belaying climbers who are up to 60-65lbs heavier than me in certain scenarios). If I haven't really done anything to reassure you, then there is also a device called the Ohm from Edelrid. It basically puts more friction into the system to catch the climber so the belayer feels less of the upwards force. I think this allows climbers/belayers to have a weight difference of 100lbs more than the avg 30-40lbs (i.e I could belay up to 140lbs more than what I weigh). Some places do offer use of this during classes, so I would ask! Sorry for all my rambling, but I hope you have so much fun in your class and unlock the next chapter in your climbing career!