Individual or professional amazon seller account for a first product?

Small thing on timing. The Pro fee starts when you register, sales or not, so if your stock is two months away that's two months of fees for nothing. Register closer to launch, but leave a few weeks for verification because that's the part that usually drags.

Depends on volume and whether you want to run ads. Individual is $0.99 per item sold with no monthly fee, Professional is $39.99 a month, so the break-even is roughly 40 sales a month. But if it's your own product, not resale, you'll almost certainly want Pro anyway. Sponsored Products ads, the Buy Box and most of the Brand Registry tools are Professional only, and a new private label listing with no ads gets very little visibility. You can start on Individual and upgrade later, it doesn't reset anything.