If you can afford an ASIC then no: it's not late, although is not really simple...
GPU mining on Litecoin is still profitable since it uses scrypt, making the processing power of an ASIC or FPGA not that significant. Some people mine Litecoins just to sell them for Bitcoins, you may do it as well :)
Fairly early miner here, I turned off my GPU miners months ago. It's really not worth it unless you have ASICs, but even then it comes down the electricity cost and the increase in difficulty now that ASICs are available.
I would only advise you to buy an ASIC if you live an area with extraordinarily cheap power. In the US this means probably somewhere between $0.05 and $0.10 per kWh.
Even then, its impossible to know how much the difficulty will increase.
because its proof of work relies on memory bandwidth, as I understand it. ASICs are possible (and in development) but are intrinsically more expensive to produce because of memory requirements.
GPU mining on Litecoin is still profitable since it uses scrypt, making the processing power of an ASIC or FPGA not that significant. Some people mine Litecoins just to sell them for Bitcoins, you may do it as well :)