First kayak and want to go saltwater later

Hi. I've decided to finally get a fishing kayak but am looking for feedback on what size to get. I plan to stick to freshwater lakes/ponds as I learn but want to be able to fish saltwater bays / inshore in the future when I am comfortable and have the proper equipment.

I looked at various brands and models and decided on Native Watercraft, only to find that the Slayer Max 12.5 was discontinued this year. I thought that would be the best size for what I want, but the alternatives in that size, the Titan and Hammer, are too heavy / too expensive.

After looking around some more I managed to find a shop with one Max 12.5 left. They offered me a little bit of a discount, but because of the store location I would have to pay sales tax. Alternatively, I could get a Slayer 10 Max where there is no sales tax, but at MSRP with no discount. This makes the prices somewhat close to each other, though there is an extra hour of driving time for one.

Anyone have any thoughts on kayak size or these particular kayaks for saltwater? I probably won't ever be trying to go miles offshore in one.