Yes do let your pup meet other dogs, you have a window now of about a month to six weeks depending on breed, where socialisation is critical to your pups relationships with other dogs for life. I would say in general older dogs give a young pup a lot of leeway, as they are no threat to them, and mostly they will sniff and then ignore them.
Please please do let your little one off the lead, where it is safe to do so, they won't go far as they will see you as a mother figure. Be calm and confident, then pup knows there is nothing to worry about. As a poster said above every emotion you feel is transmitted down the lead to the dog, so,if your scared it will pick this up.
I don't know what the breed is, but try not to pick it up away from other dogs, I see a lot of people do this with small breed dogs, lifting them up out of the way of other dogs, bend down to comfort it while the other dog passes.
While all my pointers were young from the day after I got them and before they could be put down on the ground outside anywhere other than home, I would carry them up and down the street just chatting and talking to anyone, with dogs or without. I would take them out with the other dogs carrying them in a sling. It was exhausting, but so worth it to have non reactive dogs I can take anywhere.
Good luck, and above all enjoy your dog!