"This pregnancy has been different than my first pregnancy in many ways," Jessa admits in Counting On clip

The excitement of meeting baby Seewald No. 2 is building for mommy-to-be Jessa (Duggar) Seewald.

In an exclusive sneak peek at Monday’s Counting On, Jessa hears her precious baby’s heartbeat for the first time with the help of big sister Jill (Duggar) Dillard.

In the clip, 24-year-old Jessa marks 18 weeks of pregnancy by visiting the Dillards with her husband Ben and their son Spurgeon, 1.

“Well Jess, do you want to listen to your little baby’s heartbeat?” Jill, who’s trained as a midwife, asks her sister while bringing over the monitor.

After hearing the sound of her baby’s strong beating heart, Jessa smiles widely and says her second pregnancy is finally feeling “real” to her.

“This pregnancy has been different than my first pregnancy in many ways,” Jessa says during a confessional interview. “I’ve had way more food aversions and certain things like coffee, chicken, popcorn, random other things — we couldn’t even have them in the house. I didn’t have that with Spurgeon.”

Jessa and her husband Ben exclusively revealed to PEOPLE in August that they are expecting their second child in February. “We are overjoyed to announce that Spurgeon has a new title in life as ‘big brother!’ ” the couple, who wed in November 2014, said in an exclusive statement. “We are so thankful that God is adding to our family.”

Counting On airs Mondays (9 p.m. ET) on TLC.