BTC is a little above $5,000 now. Can I still buy it? Is there any chance that it would rise further before the end of the year?
yes and yes.
you can always buy a small amount of bitcoin, you do not have to buy 1 whole bitcoin. you decide from where you want to buy bitcoin. (for example Coinbase) then you deposit whatever amount you feel like it (for example $200) then buy a portion of bitcoin with it (about 0.035
BTC).
there is always a chance of more rise. specially in long term.