My baby (born on 20/1) also has same problem. PM VSD - 7 mm & 4 mm ASD at week 1 of birth. ASD is slowly shrinking in size (3 mm now). However VSD has increased to 11 mm. Doctor has recommended surgical closure. In your case, if the size remains same and critical situation does not arise then you may wait till baby is 1 year or more. At time of surgery, baby weight 8 -10 kg is recommended. After surgery, precautions are to be followed for 2-3 months i.e. till body has recovered from operation.. Generally PM VSD do not close on their own. If you let the the situation remain as it is then child may suffer frequent infections (lung related) and in long run (i.e. 10-15 years) there is chance that some critical infection might develop in heart. Hence, closure by age of 2 is recommended. Till that time, you must take utmose care in terms of hygiene (oral and surrounding) of baby.
P.S. - I am not a doctor. My answer might raise fear in you or other parents reading this. However, after surgery, most childern lead normal and full active life. The time till VSD exists, the immunity of child is low hence care is required.