This is the type of thing that you should ask a sheilah about, since I would imagine that it really might depend on the individual. It’s possible that the facts that you are in the process of becoming Frum and that you are a single girl in the process of trying to get married would be reasons for allowing you to be more lenient.
If you want my opinion, I think that some of the things that you are asking about are things that might not matter so much which way you do. I really don’t think it matters which bedtime Shema you say. There are no issues of making a bracha l’vatala here. And if you chose the one that is more likely to motivate you to say it, that sounds like a good choice to me.
Btw, I could be wrong, but I don’t think you are obligated in bedtime Shema – certainly not the parts after Shema and V’ahavta (besides possibly the bracha of hamapil, although I don’t know if that is different for Sefardim). I think that most girls and women do say the entire bedtime Shema and it’s a very good thing to do, but I don’t think it’s something you should feel pressured about if it’s too hard for you. And I certainly can’t imagine it matters which one you say.
In terms of havdala, do you usually make it yourself or hear it from someone else? If you hear it from someone else, I don’t think it matters. If you make it yourself, I also don’t think it would matter – it probably depends what type of differences you are talking about. If the differences are before the brachas, I don’t think it would matter.
You really should ask a Rav who knows you or at least knows your situation. If you ask a Rav who doesn’t know you, make sure you explain some basic details of your situation – for example, that you are in the process of becoming religious, and that you are a single girl hoping to get married soon, etc.
But until you have a chance to ask, I think you should chill out and continue doing things the way you have until now until you hear differently.
When you do ask a sheilah, one thing you may want to ask about is brachos. One of the big differences between Ashkenazim and Sefardim has to do with which brachos women are allowed to say.