Even as VN Platinum I believe the first 3 rows of economy are a paid seat selection. I believe Platinum gets a 50% discount and Titanium gets a 25% discount. However during online check in you should be able to select those for free.

In my experience the staff at the counter are very understanding and will recognise your Titanium status, and if there are any remaining bulkhead seats they would be happy to sort that out for you. Hope you have a pleasant experience!