MTA certification addresses a wide spectrum of fundamental technical concepts, assesses and validates your core technical knowledge, and enhances your technical credibility. Note MTA exams do not qualify for MCP certification, nor are they a prerequisite for MCSA or MCSD certification.
The bottom number is the more important of the two. The bottom number of your BP (104) is a bit high. That's the pressure in your blood vessels after your heart has contracted and is now at momentary rest. Average is about 80. Your upper number (128) corresponds to the pressure in your vessels when your heart contracts.
My recommendation basically is to ask your health care provider what they would consider a low for you. Blood pressure ideally is supposed to be between 100 to 120 systolic (top number) and 70 to 80 diastolic (bottom number). In reality, blood pressure readings should be taken in context, looking at the individual, their age, and what medical conditions they have.