That is about what that advice is worth.
First, there is no such thing as "extra BAH". You'll spend every penny of it - especially if you want a decent place to live.
As a junior enlisted person, you won't make much money. As a nuke, you won't have time to spend with her until your entire first enlistment is over.
I'm going to say that again - as a nuke, you will not have time for a wife until you get to shore duty. Shore duty doesn't happen during the first enlistment.
Everything in that last post was short-sighted and for the wrong reason.
Marriage is about a LIFETIME together. It is not about having her with you when you finish boot camp. It is not about the extra allowances that married sailors get. It isn't about money or convenience at all. If you marry for those reasons, expect it to fail.
If the two of you cannot stand to be geographically separated, she can get a job near your duty station, get her own apartment (which will be HERS and not yours) and the two of you can continue your engagement until you are actually ready for marriage. "Financial security" and being a first-term enlisted person do not even belong in the same sentence. The best security you can give her is your mature, thoughtful, and dedicated commitment to her happiness. This does not come from your measly Petty Officer Third Class paycheck. It comes from wise, and sometimes very difficult and painful, decision-making.
Neither of you has any idea (and neither does LuckyKid) of what you are about to get yourself into. It is a good start on life. It is a foundation for immense future growth in or out of the Navy. It is NOT a time to be starting a marriage. A person who is already in an established marriage - emotionally, financially, and otherwise - can start the nuke pipeline and come out still married. A person who is in the pipeline won't have time to be married. If you think that having a spouse in an apartment near the base, whom you will see almost not at all, is the way to build a relationship, you aren't going to make it. You need to spend time with each other - lots of time over the course of a few years. A newbie nuke can not do that.
Friend, you need to wait until you have spent at least two years on sea duty before you have the right to ask that woman to be your wife. You may be "engaged" at this moment, but the person who put that ring on her finger is not the same person who is going to be you in a couple of months.
If you love each other - wait until you can do right by her. You want to be married. I understand. Marriage is for adults. You are an adult - so do the adult thing. Resist the urge to marry for all these wrong and trivial reasons. Do it when you are CERTAIN that your job won't destroy it - and not a moment sooner.
Good luck to you and your intended. A few years is nothing compared to a lifetime of happiness. It is not such a great sacrifice when you consider the reward. You will not regret waiting - the opportunity will still be there before you as long as you still want it. But you will regret rushing and wasting the opportunity.