A little bit about myself, I am a sailing Chief Mate, 27 years old and have received my ITA in September 2018.
I will answer your query in 3 steps :
1) Age is a very big factor unless and untill you have secured a job offer from Canada. If you look at the rating system, one of the highest points have been given to age. ( 30 years of age or less ).
2) Regarding the work experience, I am a sailing Chief Mate presently so I think I can give a apt solution to this. Since I have a good rapport with my company, I requested them for a work experience letter without mentioning that it is a contract based employment. After some amount of convincing they did give it to me. Maybe you can try this?
3) NOC 2273 is in demand. But again there is a big catch. Canada requires that you have a Canadian Certificate of Competancy, which can only be awarded to Canadian Citizens or Permanent Residents of Canada.
Basically if you hold a COC of a different nationality, you will have to visit a Transport Canada Office, request for an equivalent exams and do all the associated courses as required by them after you get your PR.
In conclusion, since age is not on your side, I think the solution given by your visa consulatant is good. Once you have Canadian Education the odds might be in your favour.( Altough still a long shot )