C172 pilot reported flying too low over rising terrain to avoid clouds.

Narrative

During my direct flight from ZZZ to ZZZ1; I was concerned that I might be flying too low; especially as I transitioned from the oceanfront area inland. ZZZ Departure offered me the option to climb out over the ocean to avoid the clouds; but I chose to remain below them and continue under VFR conditions. As I flew inland; I did not adequately account for rising terrain elevation slowly inland; and so while my altimeter indicated about 900 feet; the actual ground level was higher than I expected; reducing my clearance. The terrain beneath me during my flight was mostly dense forest with very little to no residential housing; apart from some highways and backroads. The cloud bases appeared lower than reported; around 2000-2500 feet instead of 3000-4000 feet; which influenced me to maintain a lower altitude. Once I recognized the reduced terrain clearance; I promptly climbed to a safer altitude. Throughout the flight; safety was my top priority; and while the distance from clouds and terrain may not have been ideal; no unsafe conditions occurred. I consider this a valuable learning experience and will plan more conservatively in the future; including opting to climb above clouds when feasible; especially before obtaining an IFR rating.