Needing a bit of advice please .. what would you do ?

I am booked in for puppy training classes starting Monday. We don't get Pickle until 31st March but the lady at the training class has a puppy for us to practise with. She is suggesting that we bring him along when we get him. BUT obviously he will only have had his first set of injections. She said it wouldn't matter as all the puppies are either fully vaccinated or on their first set but to go with vet's advice - some say yes some say no apparently.

I don't know that I feel comfortable with taking him before his second injections have taken effect. I don't mind attending and learning with another dog because I can obviously put into practise with him when he gets here. I also think it would give me some confidence too!

So would you take him before the second injections or not? Thanks x