Trying for another child

Hello mummies. Is it true that it's harder to conceive for second child? My friend said they have a hard time conceiving second child. They are arnd 30+ I had my first child in early 20s, now I'm near mid 20s. My menses cycle is always on time. My partner is also arnd mid 20s. I heard it's easier to conceive at a younger age. Hence, hearing that from them. I'm kinda confused. Is it really harder to conceive for second child? Thank you.