Hazelrah,
Although some astrologers will assure you they can rectify your chart, and will charge you a lot of money to do so, rectification is very involved, and hard to get accurate. If you know *roughly* your birth time, and have a good diary with exact dates of crucial events-like the day you left home, or started college, or got injured, etc etc then it *can* technically be done.You do need a lot of events though.
One of our members here, Arian Maverick, has basically spent years here rectifying her chart-I think recently she expressed confidence that this one felt right.Maybe you could pm her, to discuss the process she went through.
Personally I have not found solar arcs to be reliable, although some members *swear by* them.
In your position I would make every effort to get hold of a birthtime.Even if you are adopted, records of your birth time do exist-I found mine, at a hospital that archived birth records for the district I was born in.
If you weren't born in a hospital, I'd be finding out who was there, who may recall.Your mother doesn't know?
In the case of adopted persons, the papers involved should at least give you some very important dates to start a rectification process, but if you are new to astrology, this could be a slow, but very worthwhile process.
Cheers
Lilly