I think that advice makes sense. Ideally put away more than 15% of your gross income if possible, but I think the general advice is that you should be saving 15% of your gross income every year. Whether part of that 15% of gross comes from employer match or directly from you doesn’t matter.

I think my employer did have a grant or something for new hires as well. The other thing I think they have is automatic increases annually of 401k contribution. So just in case you are an employee that doesn’t manually go in to modify contributions, those employees will automatically have an increase of 1% contribution to 401k every where up to a certain upper limit, iirc.

Good luck on the retirement. Hope it works out. Also, when you look at the calculators to project future retirement, they tend to assume the market will greatly underperform historical market performance. For me it looks bad on that default. When I flip the project to match historical performance, or out perform historical performance, my retirement looks excessive. So save as much as you can and follow the guidelines, but there is some luck of market factors involved as to how you will end up.