Sheba is very young. Premiums go up with age. Your low premium might also reflect lower vet fees in your area. Go to their quote app and plug in the same info except try it with different ages and see what your premiums would be.
Beau is 3, and intact, and Trupanion quoted $63 a month for his premium here in Tucson, with a $300 deductible per injury/illness. Exam fees in Tucson range from $30 to over $100, depending on where you go. Changing his age to 6, 10, and 13, premiums went up to $86, $125, and $151 respectively. No doubt they’ll be higher when he actually hits those ages, as prices rise for vet care.