Would you consider buying used items? Or would you only consider new from a store? With proper guidance, education, and research, buying used items can save you alot of money. I will base my next paragraph as if you are willing to buy used equipment.
Ok, so birds seem to be the main interest (which so happens to be my favorite subject). To be honest, a nice birding lens is gonna cost a good chunk of change. In the used market, you are looking at $850 or more, and that would be finding a Canon 400mm f/5.6 for a bargain price. If you want a more flexible lens, the 100-400mm that I have is very good, but a few more hundred $$$. When talking about birding lenses, hundreds of dollars are talked about as if chump change unfortunately. Many serious bird shooters spend in excess of $5,000 for a single lens!!! That's not in my price range, unfortunately, so I am telling you about the birding lenses that will provide superb results and still have a "reasonable" price of around $1,000. So, as recommended above by some other posters, it's not a bad idea start out using your mom's camera if she'll let you and saving up for a nice lens, unless you already have the cash in hand. I would suggest starting out with a lower priced used camera body in great condition, something like a used 30d or 40d, the 40d would be ideal if you can swing $550-600 for one because the autofocus system is very good and there's lots of good bird photographers still using that camera. It is a better action camera than the T1i. Not that the T1i can't get good action pics, but the 40D is more made for action with better autofocus, more frames per second, and better/sturdier build. If the 40D is out of budget, the 30D is a good alternative and costs a couple of hundred $$ less. Do alot of research and save up to buy the right equipment the 1st time, there's no sense in buying the wrong tool for your needs, it will only disappoint you.