@MamaHippo There is a lot of information on the Internet, of course. I am not an expert, but BPD Central looks good to me.
Unfortunately a lot of websites still have out of date information from before 2011, when the official definition of BPD changed. If you see something like, "five or more of the following" and then a list of nine things, that's the out of date version.
It is not possible to diagnose yourself from things you read on the Internet. To be sure about whether you have BPD, you would need to seek professional help, maybe by starting with your doctor and getting a referral for assessment by a mental health professional.
Charlie