Hello, Thanks for writing to Health Care Magic, I am Dr Muhammd Ahmad, I have closely read your question and I understand your concerns, I will hereby guide you regarding your health related problem. Low BP is not a concern in this age if she has no problems like vomiting diarrhea diebetes, usually young people don t take much fluid and salts in their food , they usually take fizzy drinks etc, with which they lose further quantity of fluids. When ever your daughter feels any problems like that you should check her blood pressure if its above 90/60 then no worries if below than you can simply give her a couple of boiled eggs with salt sprincled on them and she should drink much fluid at that time. If she frequently gets this problem she can just increase her salt and fluid intake and everything will get fine with time.There is nothing to panic in this case. I hope this answered your question, if you have any queries feel free to ask. Regards. Dr.Muhammad Ahmad. General and Family Physician..