Short answer
Yellow leaves have several possible causes, and the published guidance is that overwatering is the one it turns out to be most often. Check the soil at depth before you do anything: wet soil points at water or drainage, dry soil points at thirst. Feeding is the common first instinct and it belongs near the end of the list, not the start.
Listed in the order they are worth ruling out. It is normal for more than one of these to be happening at once, so work down the list rather than stopping at the first match.
This is the first one to rule out because it is the most common. Yellowing has several possible causes, and overwatering is the one it turns out to be most often.
What to check first
Push a finger into the soil up to the second knuckle. If it is wet down there and the leaves are yellowing, you are looking at water rather than thirst.
You said this plant is new. Plants sold at a garden centre were grown in a greenhouse, and lower leaves yellowing and dropping is a documented reaction to being moved from that into a darker, drier room.
What to check first
Count back. If the yellowing started within a couple of weeks of bringing it home, and it is the lower leaves going first, this is the likely explanation rather than anything you did.
Worth ruling out early because it is easy to check and easy to fix. A plant kept in poor light for a long stretch yellows, and the yellowing usually arrives alongside other signs rather than on its own.
What to check first
Look at the growth, not just the colour. Thin stretched shoots reaching toward the window, wide gaps between leaves, few or no flowers, and very little new growth together mean light.
The opposite of the first cause, and the reason to check the soil before acting on either. Lower foliage yellows when a plant has been too dry for an extended stretch.
What to check first
Feel the soil at depth rather than at the surface. Dry all the way down, a pot that feels light when you lift it, and water that runs straight through in seconds all point here.
Ranked below light and water on purpose. Yellowing of the lower leaves is generally caused by a nitrogen or iron shortage, but the published guidance is explicit that poor light and overwatering produce the same look, so this is what you land on after ruling those out.
What to check first
Ask when it was last fed and how long it has been in the same soil. A plant in the same pot for a year or more, watered often, with pale lower leaves and healthy new growth at the top, fits this.
Mentioned last because it usually shows up as a reason one of the causes above arrived. Plants that have filled their pot are especially prone to running short of nutrients.
What to check first
Look at the drainage hole for roots coming through it, then slide the plant out and look for roots circling the outside of the root ball in a dense mat.
Still not sure
This is exactly what your county Extension office answers, for free. They are the local horticulture experts for your area, they know what is going around this season where you live, and they will look at a photo.
Find your local Extension officePollinator Patch gives you watering and seasonal care for the plants you already own, written for your region rather than for gardening in general.