Any HPD officers here? I want to start the application process when I turn 20.5 and have some questions.

So I’ll have the required college credits by the time I begin the application process but have a few questions. I want to work at HpD but the pay is kind of iffy compared to other departments. But it is the closest to my area compared to places like Humble or Pasadena which pay a lot more .( I live in Cypress). Do y’all know if I start off at another department and then transfer to HpD, will I be getting paid as if I am on my 3 year in HPD when transferring, like lateral entry I believe. Also wondering if I transfer over to HpD would I have to restart my retirement years for the pension. I don’t know if I’m being confusing but for example I know a lot of departments have a 20 year minimum before they can retire and get their pension, so those 3 years I am not in HpD but transfer to HpD be added for my retirement or would I have to work 3 more years in HpD in order to get the 20 years. Also wondering how difficult would it be to promoted to sergeant because I know you have to wait 5 years for that. I really want to work at HpD in order to work in the human trafficking division and am wondering if it’ll be worth it in my end. Thanks in advance for answers!