dude did not ask about insurance, why make assumptions about his situation?
great starter bike, go for it
The assumption with the CBR125, or any street bike, is that, as a street bike, he will want to ride it on the street. I believe this is a good assumption. Very few people own their own road course or start riding by going to a track. The OP is a newby, we should, and do, answer questions as yet unasked.
OP, Anything <500cc <50hp < 500lb is a good starter bike. This removes all of the 600cc sport bikes. Lighter bikes are nimbler and easier to keep upright, when you have a mistake. A 125 is a great size to learn on, but is limited to ~80-90kph, unless you pin it wide open. Also consider the 300cc bike category. The weight of the bike is not much more (easy to get used to) and there's more power if and when you want to try the boring highway.
Insurance premiums will probably be more expensive than your bike's initial purchase price, and this premium is yearly. Check insurance first before you buy anything. Insurance differences between the 125 and 300cc bikes may not be very much, so ask around.
To reduce the price of your first bike, consider used and consider other styles. You might be able to get a small cruiser for cheaper than the CBR. If you need to tip toe to sit on the bike, this is Ok. You will get used to it and it will not slow you down. It all depends on if your legs are long or your torso is long.