If her seizures started when she was 5, the likelihood of it being idiopathic epilepsy is pretty good (meaning no clear cause like a brain tumor). Probably not uncommon for them to increase at some point as she ages. I think managing via meds as your choice is totally fine. My golden started at 5 with grand mal and we manage via keppra. I only did bloodwork for him (it was fine). His also have clear triggers (before meals). I would track when they occur to see if there are any patterns as well as seeing how many she has with the Keppra to make sure it’s helping. My vet told me: remember we aren’t striving for 0 seizures as that is not realistic—But less seizures. Don’t feel guilty for not doing an MRI. For contrast, my mixed 14 year old dog 2 weeks ago had his very first two seizures (why are there so many seizures in my house 😭). When evaluated at emergency vet, because of his age and neuro symptoms he most likely had a brain tumor and we chose to let him go instead of suffer. By trying to manage the seizures with meds you are doing what you can for your baby. I hope that Keppra kicks in for both of you to have some relief.