The OP was asking about Irish Gaeilge as an alternative to Scottish Gàidhlig because he couldn't find any Scottish Gàidhlig learning sources.
He is perfectly free to learn Gaeilge of course, but if he wants to learn Gàidhlig, there's nothing stopping him. I don't think it's an easy route to learn Irish Gaeilge first if you want to learn Scottish Gàidhlig. I had my first Gàidhlig lessons in 1970 at the age of 10, and I am still learning the one language 40 years later!

Here is a refresher list of FREE online resources:

Akerbeltz - A’ Ghobhar Dhubh
(the Black Goat)

Colin & Cumberland learning games (This is very funny, my kids love it)

Colin & Cumberland online episodes (again, very funny)

Beag air Bheag, Scottish Gaelic for absolute beginners.

Air Splaoid! twelve lessons for beginners

Dealas (aimed at teenagers, but enough online for anyone to learn)

Bruidhinn ar Canan (some intro lessons)

The Highland Council Gaelic Toolkit

Basic Gaelic for Parents

Gaelic4parents

Scottish Radiance - Words and phrases for beginners, some with Real Audio

.........and there's LOADS more out there, try entering Speaking Our Language Gaelic in YouTube, for example.