The sister is probably mad at you because you are getting a good education to be a medical professional, hence making more money than her kids, more security pension wise, better furniture, better self esteem than what her children are going to obtain as they are being told to pioneer and get a part time low end job to support themselves in these "last days"---- and you are a shining example of the opposite - so she has some axe to grind against you.
There will always be those types in the congregations - the love that is mentioned is apparently a choice for those who feel entitled to discredit others.. Tread carefully. This is from someone who is in a congregation. They will smile, pat you on the back, etc. but you are a single person - if a male you will get a wife, if a female you will search for a JW husband who can tell you what to do as he will be your head- male JWS are in short supply.
You appear very spiritual, this is a good thing, however, please do some fact checking about the Australian Royal Commission report that is on the Internet. Read it very objectively. You will gain some insight as to what you are getting into. But on the other hand, this may be what you want and if so, it definitely is your choice to make.