[Help] Introducing Puppy with incomplete vaccine to another Dog

Hi all! So my cousin's puppy is 4 months old and only has 1 vaccination left and she's complete. She's done with all the 5in1 vaccines and the most recent one she had was Anti Cough. Will it be okay for my cousin's puppy to meet with my 1 year old dog for early socialization?

I have 2 dogs so my 1 year old dog has been living with another dog for about half a year now.

Tips for introducing dogs to one another will also be a very big help, thanks!