Rental Income or Buy First Home?

I recently graduated and started work around 8 months ago. I still live with my parents for the time being, but have tried to save ⅔ of my salary every month.

I was thinking about buying a house later this year and start my life(move in with girlfriend, propose, start marriage plans), but then I thought of an alternative plan that would honestly be horrible for the time being, but could pay off big time in the end.

[Plan B]I thought about instead investing the money I’ve saved and renting a really nice apartment in a nearby major city and renting it out on Airbnb, Homeaway, etc. for passive income. I would then build that income over time and eventually accomplish plan A(Buy a ring, house, start marriage plans, etc.)

Obviously Plan B isn’t popular at all with my girlfriend or my parents. They don’t mind me living at home for longer, but think this isn’t a great idea and rather me invest in a home of my own before thinking of rental properties and passive income.

My only worry is that once I buy a house and start my life that it will be difficult to amass enough money to easily perform the same plan later on. What do you all think I should do? Plan A? Plan B? Something in between or completely different?

TL;DR Buy a house, plan for marriage, buy a ring? OR Rent an apartment out and make a profit using Airbnb and similar services to bring in passive income, buy a house, ring, plan for marriage a little later(1–1.5 years later)?