Do you have Dish Network? If yes, then you are very likely to have DSL.

When you call tech support for your internet, are you speaking to someone with an Indian accent, or do you get transferred to a department with Indian accents? If yes, you have DSL.

What model is your router? Is there a second router/modem very near it with a sync light? If yes, you have DSL.

If you have fiber, they would have had to install an ONT in your home, typically in the basement or garage. These are typically white/gray/beige boxes mounted to a wall near your electrical circuit box.

I did forget that a very small number of customers were mandatorily moved from DSL to fiber and provisioned for 3 down/1 up. However, their pricing did not change.

I don't believe there have ever been fiber provisions lower than that. There also are rare circumstances of apartment buildings that are too old, or for some reason unable to be wired for coax (typically an exclusive contract with another television provider) where fiber is ran to the building, and then converted to DSL from the ONT in the building to your apartment. This is almost always in New York state, and never the case for single family homes.

Regardless, you shouldn't be, and very likely are not, paying $100 for only internet service. That could be a bill for FiOS triple play service (phone, internet, tv), FiOS double play (internet and either phone or television), Verizon double play (phone and DSL) plus Dish Network, or some other combination of DSL and telephone or television service.

$100 a month for standalone FiOS internet service would get you at least 50mbps down anywhere that FiOS services. More likely 75mbps, and possibly even 150mbps service.

You really should look in to what exactly you are spending $100 a month on. If you really are paying $100 for only FiOS internet, you very likely have a technical problem preventing you from getting your provisioned speeds.