Your approximate location will give us your climate.
If the trusses run all the way out to a support beam on that porch your plan may be possible, however the trusses are currently supported by the front wall of the house and the extension may not have anticipated carrying that load. Especially the front of the porch which probably has a post or two.
In any case you may need stamped plans for your permit application, towns are like that. Your change alters the footprint of the house thus the evaluation and taxes.
Bud
If the trusses run all the way out to a support beam on that porch your plan may be possible, however the trusses are currently supported by the front wall of the house and the extension may not have anticipated carrying that load. Especially the front of the porch which probably has a post or two.
In any case you may need stamped plans for your permit application, towns are like that. Your change alters the footprint of the house thus the evaluation and taxes.
Bud