Some yellowing on the lower leaves is normal in hot summer weather, but your plant actually looks like it's lacking something. I suppose it's magnesium. If you have access to epsom salt, I highly recommend making a spraying solution (1 teaspoon to the gallon of water) and hitting the top and bottom of each leaf.

Thank you

If it was used to shade (in the store) and now is suddenly put in full sun, it could be reacting to full sun. Can't tell if it needs repotting.

Well, I have had it for 2 months now. And it has just started turning yellow in the past week.